Sydney Bristow discovers that her job as an agent for SD-6, a top-secret division of the CIA, holds some deadly secrets that threaten the security of the free world. Sydney finds that her father, Jack, is also SD-6 and that the group is not part of the CIA, but actually an enemy of the United States.
Sydney returns to SD-6 and is assigned with Dixon to travel to Moscow to retrieve some stolen files. But when Sydney discovers that she has inadvertently given SD-6 access to a nuclear weapon, she is forced to travel to Cairo and face a deadly foe. Meanwhile, Will begins to question the circumstances surrounding Danny's death, and Sydney learns of her father's involvement in the murder.
Sydney's life is in mortal danger as she is sent to Madrid to retrieve a 500-year-old sketch that contains a set of numbers and meets up with her deadly nemesis, K-Directorate agent, Anna Espinosa. Meanwhile, Will delves deeper into the cause of Danny's death and discovers a very strange anomaly.
Sydney and Dixon go on a dangerous case involving the safety of the United Commerce Organization. Francie confronts Charlie about his secret date with another woman, and Will continues to get closer to the truth about Danny's murder.
Sydney's secret double agent status is jeopardized after smuggling a biotech engineer into SD-6 from her mission in Berlin. Will meets a woman who confesses that she was having an affair with Danny shortly before his death. Vaughn informs Sydney that her father may be working for a third secret operative agency.
Sydney goes undercover in a mental institution to get information from Shepard, a man who has been unconsciously programmed to be a deadly assassin. Will discovers the true identity of the woman who claimed to have an affair with Danny. Marshall finds the computer worm planted in the SD-6 mainframe by the CIA.
While helping Shepard escape from the asylum in Bucharest, Sydney discovers the shocking connection he has with her past. Meanwhile, after tracking the computer virus secretly planted by the CIA, Sloane is confronted by Alliance representative Alain Christophe, who suggests that one or more moles may have infiltrated SD-6.
Sydney must undergo an extensive lie detector test to satisfy Sloane's frantic search for the SD-6 mole. Meanwhile, with nemesis Anna Espinosa following her every move, Sydney seeks out the connection that a device may have to the 500-year-old prophetic Rambaldi sketch.
Sydney's life is placed in mortal danger when Sloane is informed by his superior that she is the SD-6 mole. Meanwhile, Dixon's life hangs in the balance after he is shot on a mission, and Will realizes that his discovery of Kate Jones' pin could uncover some unexpected information.
Jack has to find a way to save Sydney when he discovers that Sloane has ordered her tortured and killed for being the suspected SD-6 mole. Will may be making the mistake of his life when he begins to research a name heard on a mysterious audiocassette -- SD-6.
Sydney is grateful and proud of her father after he saves her life while on a case in Havana. But her admiration is short lived when Vaughn discovers further evidence that Jack may have been responsible for the deaths of over a dozen CIA officers many years earlier.
When armed intruders take over SD-6, led by McKenas Cole, a man bent on exacting revenge on ex-boss Sloane, Sydney and Jack must work together to save their colleagues. Meanwhile, Will fears that his investigation of SD-6 and its link to the murder of Eloise Kurtz is placing his life in jeopardy.
Vaughn disobeys orders and attempts to help Sydney and Jack avert the destruction of SD-6 headquarters and all its occupants. Meanwhile, McKenas Cole continues his vendetta against Sloane and searches for a mysterious device.
Sydney and Dixon are sent to Las Vegas to gather information from a K-Directorate agent who has ties to the group that attacked and nearly destroyed SD-6. Will begins his journey in discovering what SD-6 really is.
Sydney is tested by the DSR to discover her mysterious link to a chilling 500-year-old picture and prophecy foretold in a Rambaldi manuscript. Meanwhile, after uncovering the identity of the rogue group leader, "The Man," Sloane learns through fellow Alliance of Twelve member Edward Poole that a close friend may be in cahoots with the enemy.
While the FBI detains and questions Sydney about her past and possible ties to a mysterious Rambaldi doomsday prophecy, Vaughn and Jack must race to free her and find a way to clear her name before her cover is blown and SD-6 is made aware of the situation.
While on a case to track the activities of Khasinau, Sydney runs into her ex-lover, Noah Hicks, who broke her heart and left without saying goodbye five years earlier. Jack is ordered to see CIA psychiatrist Dr. Barnett to help him deal with his churning emotions after discovering that his wife may still be alive.
Sloane begins to question where Noah's true allegiances lie, as passion ignites between Sydney and Noah. A rogue assassin known as the Snowman is dispatched by K-Directorate to kill Khasinau, a.k.a. "The Man".
In order to catch Khasinau and get closer to finding her mother, Sydney and Vaughn set up an undercover transaction for a Rambaldi artifact with Khasinau's representative, Mr. Sark. But Sydney's cover may be compromised when a SD-6 agent is sent in to thwart the sale.
Will's life is about to change as he is sent to find the person responsible for leaking information to him about SD-6. Meanwhile, Sloane finds himself on the cusp of finally tracking down Khasinau when SD-6 captures "The Man's" right-hand man, Sark. Dixon becomes suspicious of Sydney's activities.
In order to save Will's life, Sydney and Vaughn must destroy a familiar looking Rambaldi device, while Jack makes a risky deal with Khasinau's representative, Mr. Sark. The Alliance comes to a decision regarding the fate of Emily Sloane and Sydney finds herself face-to-face with "The Man."
Sydney finds herself face-to-face with her mother, whose intentions for her daughter are made chillingly clear. Meanwhile Sydney continues her search for Vaughn, not knowing if he is dead or alive after being swept away by a wall of water in Taipei.
Sydney must decide whether her mother's goodwill gesture was sincere or an attempt to kill her. Will witnesses Francie discussing her restaurant plans with a man whose affiliations are questionable, and Sloane is made a full partner in the malevolent Alliance of Twelve.
Sydney must outwit Sark in order to find a crucial piece of intel. Meanwhile, Jack faces Irina for the first time in almost 20 years. Will finally meets Vaughn and Sloane is haunted by his wife's death. Sloane, who drinks only water is seen drinking whiskey in his office.
Sydney discovers a terrifying secret when she's sent on a case to track down a new generation of weapons. Meanwhile, Vaughn suspects Jack of setting up Irina to take a fall. Sloane tells Jack the truth about Emily's death.
Sydney's trust in her father begins to fade. Meanwhile, Sydney and Vaughn may have been exposed to a deadly virus while in Taipei; Sloane, haunted by Emily's death, begins to unravel. Vaughn enlists Will to help research a case.
Sydney races to find a cure for Vaughn, but in order to find the antidote, Sydney must make a deal with Sark that could endanger Sloane's life. Meanwhile, Will continues his research for Vaughn and discovers some disturbing inconsistencies involving 20-year-old standardized IQ tests.
Sydney, Jack and Irina must put aside their differences and go undercover as a loving family in order to seize six nuclear warheads from an abandoned facility in Kashmir. Meanwhile, Sloane announces to a suspicious staff that Sark will be working with SD-6.
Sydney and Jack continue on a mission to take control of six nuclear warheads. Irina meets up with Gerard Cuvee and we discover where Irina's loyalties lie. Meanwhile, Sloane informs the Alliance that Emily may still be alive.
Jack meets Alliance counterintelligence head Ariana Kane, who is sent in to investigate Emily's disappearance and to discover who is trying to blackmail Sloane. Meanwhile, Marshall is sent on his first mission with Sydney as his partner.
While Alliance counterintelligence head Ariana Kane tracks Sydney in order to catch her fugitive father, Jack elicits Irina's help in finding Sloane's blackmailer. Meanwhile, Sydney and Vaughn risk exposing their covers to SD-6 when they share a romantic dinner together
Sydney and Jack are confronted by the new director of SD-6, one Geiger, who replaces Sloane, whose whereabouts and intentions are unknown. Sydney and Vaughn lead the team to raid SD-6 and shut down the Alliance.
Sydney, Vaughn and Jack must determine whether CIA agent Lennox is who he says he is after his deep cover mission is compromised in Berlin. It is discovered that an agency has built a machine capable of replicating a human being's appearance.
Sydney must make a life-defining decision regarding her future with CIA, while Sloane re-emerges and continues his obsessive quest to piece together the mysterious Rambaldi artifacts -- with the reluctant aid of a kidnapped scientist named Neil Caplan.
Sydney begins to question where Vaughn's allegiances lie when she learns through CIA Agent Yaeger that he is under investigation. Meanwhile Irina and another crucial Rambaldi manuscript --this one about the secret of eternal life-- are used as bait to try to catch Sloane.
A Rambaldi manuscript prophesizes that an apocalyptic event involving a heart will soon take place. An agent is sent after one man in Panama in order to steal his heart. Dixon's grief leads Vaughn and agency psychologist Dr. Barnett to question his intentions.
Sydney begins to question Will's identity when he's arrested for espionage, under suspicion of being a double. Meanwhile Sark and Irina plot to recover the Di Regno heart, and Sloane makes Jack a business proposal.
Sydney tries to piece together the last two years of her life and discovers the fates of her friends and family. She confronts Vaughn about his marriage and learns the shocking fates of Jack and Sloane. Meanwhile, she is granted temporary CIA clearance on a case that may help her regain her memory.
Sydney's search for her past leads to a jailed Sark, but their Q&A is cut short when he becomes the ransom for a pair of abducted CIA scientists, whose kidnappers may be tied to the murder of his father. Jack contacts an old friend of sorts for info on Sloane's new world-peace project, and Vaughn makes a decision about his future as an operative.
Sydney and Vaughn are reunited again as a team to prevent Sark from destroying the nation's satellite communications system. Meanwhile, Jack must find a way to stop Marshall from uncovering the identity of a familiar murderer. Sydney accompanies Vaughn and Lauren as they meet with Sloane to ask for a favor.
Sydney discovers a link to her missing two years in the form of Simon Walker, the dangerous leader of a group determined on retrieving deadly biological weapons. Jack takes matters into his own hands to protect his daughter, purposefully revealing Sydney's deadly secret to Dixon in order to preserve her position inside the CIA.
While Vaughn's life hangs in the balance, Lauren butts heads with Sydney after learning the part she played in his stabbing. Meanwhile, Sydney further questions Sloane's allegiances after he is kidnapped by Kazari Bomani, a kingpin in The Covenant. Jack's cover is jeopardized when he meets with Simon to dig up information on Sydney's missing two years.
Sydney's emotions are turned inside-out when she comes face-to-face with Allison, Francie's doppelgänger, who was presumed dead but is now a key figure in The Covenant. Meanwhile Lauren's search for Lazarey's murderer leads her closer to discovering a connection to Sydney, and Sydney begrudgingly is assigned as Sloane's CIA handler.
Jack takes drastic measures to ensure that the NSC never finds out the truth about Sydney's murder of a Russian diplomat. But his actions place a heavy strain on Vaughn's marriage, as Lauren gets closer and closer to the truth about Sydney. Meanwhile, Sydney agrees to go on a mission with Sloane in order to thwart plans to obtain the operating system to a deadly weapon -- and she discovers an unlikely ally in the hunt for her missing two years.
When Sydney is taken into custody by the NSC, Jack and Vaughn have no choice but to ally themselves with Sloane to rescue her. As they put together an extraction team, Lauren faces an impossible choice -- side with the NSC, who she wants to believe is doing the right thing, or with her husband.
After making a shocking discovery in the desert, Sydney agrees to submit to an experimental procedure conducted by an eccentric doctor, designed to retrieve her lost memories. But while Jack and Vaughn look on, Sydney's mind proves surprisingly resistant to letting her remember her missing time -- and the process of recovering it could end up killing her.
The identity of the mysterious "St. Aidan" forces Sydney to pull a stunned Will out of witness protection. But the pursuit sends the two old friends on a collision course with Allison -- the woman who ruined both their lives. Meanwhile, a jealous Lindsey arrests Jack and Vaughn as conspirators in Sydney's escape from NSC custody.
When the Department of Special Research seizes the Rambaldi Cube from the CIA, Sydney thinks she's lost another chance to find out what happened to her missing time. But FBI Director Kendall lets her in on a huge secret, revealing how her destiny has always been on a collision course with Milo Rambaldi.
Jack contacts a mysterious woman with ties to Irina to help him free Sydney and Vaughn, who have been captured and face a North Korean firing squad. But Jack is faced with a curious conundrum when the woman tells him that she will not put the rescue plan in motion until he fulfills a favor - assassinate Sloane.
Sydney and Vaughn are sent to retrieve the Doleac Agenda to gain an advantage over The Covenant. For this, Sydney and Weiss must convince rogue security systems designer Toni Cummings to help the CIA break into a Lethal Response System. Meanwhile, Sark approaches an unlikely ally to kill the Covenant's Cell leaders.
While trying to retrieve a bomb, Sydney and Vaughn are ambushed by unidentified assailants. Meanwhile, Lauren and Sark continue to solidify their new partnership, Sloane divulges a dark secret to Dr. Barnett and Marshall shows the strains of new fatherhood.
Sydney and Vaughn must convince bomb maker Daniel Ryan that they are part of The Covenant in order to find out where he has hidden one of his devices. But Sydney discovers that her ties to the bomber could lead him on a suicide mission.
When Dixon's children are kidnapped by The Covenant he faces a tough task. With no choice, he steps down as director and enlists Sydney's help in a desperate plan to safely retrieve his children from Sark. Lauren is put to the test as a double agent when she has to work with her father.
Sydney and Vaughn must track Kazari Bomani down to get hold of a piece of the Rambaldi puzzle. Meanwhile, Jack reveals his suspicions to Senator Reed about his daughter Lauren's allegiances, and Vaughn decides what to do about his marriage.
Sydney and Jack warn a disbelieving Vaughn about their suspicions of Lauren being the Covenant mole inside the CIA. Meanwhile, Bomani and Sark take possession of the Rambaldi machine, Sydney and Vaughn must stop a Covenant virus that's crippling medical facilities around the world, Sloane's secret is revealed to Jack.
After finding out that Lauren is working for the Covenant, Vaughn is told to keep up the façade of a happy marriage in order to keep tabs on his wife's activities. But he's in for a shock when he uncovers the truth about Lauren's mother, Olivia. Meanwhile, Jack refuses to help exonerate Sloane of his crimes and put in motion a stay of execution, and a monk discloses the identity of the Rambaldi "Passenger" to Sydney.
After discovering the identity of the Rambaldi "Passenger," Sydney and Jack seek the aid of Sloane, to track the "Passenger" down. Meanwhile, after learning a secret about his father from Thomas Brill, Vaughn is kidnapped and tortured by Lauren and Sark, who are about to track "The Passenger" down themselves.
With the aid of Katya Derevko and CIA imprisoned security systems designer Toni Cummings, Sydney and Vaughn attempt to track down Sloane and Nadia. But Lauren and Sark are also in hot pursuit of them in order to uncover the secrets of Rambaldi. While Vaughn's obsession with tracking down Lauren is beginning to consume him, Sydney and Vaughn turn the tables on an old foe.
Vaughn comes face to face with his darkest demons in pursuit of his wife; Nadia must decide whether or not she can trust her father in the pursuit of Rambaldi's most priceless artifact; and Sydney receives a shattering revelation that will make her question everything - and everyone - she thought she could trust.
Sydney quits the CIA and joins a Black Ops unit called "Authorized Personnel Only" alongside Dixon, Jack, Vaughn and Sloane. Meanwhile, the truth Sydney found out in Wittenberg endangers her relationship with Jack, and eventually she reveals the awful truth to Vaughn.
Sydney unwillingly teams up with her father to hunt down a modern-day samurai. Meanwhile, Nadia doesn't want to go back to the spy business, but is forced to when Sydney's life is jeopardized. Sydney finds out the reason behind Jack's misdeed and Nadia makes an unsettling promise.
Sydney must seduce a murderous arms dealer in order to track down a stolen NSA code-breaker. Meanwhile, Vaughn fears for Weiss's life, and Sydney and Jack argue about telling Nadia the truth about her mother, and that Jack was the one who killed her.
Sydney and Vaughn are sent on a mission by APO to obtain a sample of a new bio-weapon which can literally freeze a person to death. Meanwhile, Nadia asks Jack for the truth about her mother, and Sydney begins to wonder if Vaughn has really come to terms with Lauren's death.
Sydney and Vaughn are sent to infiltrate a training camp run by the October Contingent that has been designed to resemble a suburban American neighborhood. Sydney and Vaughn find themselves in a unique position of having to 'learn' how to pose as Americans. But these civics lessons have deadly consequences for the losers.
After being infected with a hallucinogen, Sydney starts to lose touch with reality. Vaughn and Jack must rush to find an antidote before Sydney puts her life - and others next to her - into danger. Dixon and Sloane butt heads over sending Sydney into the field.
While Sydney and Nadia argue about Nadia's acceptance of Sloane's fatherly concerns, Sloane worries about Nadia's well-being when she and Sydney go undercover as wealthy, irresponsible young heiresses to uncover the whereabouts of a deadly chemical.
Sloane temporarily steps down as Director for the latest assignment which involves Anna Espinosa, Sydney's old foe. However, Anna turns the tables on APO when she captures Nadia and forces Sydney to do her biddings. Sydney tells Nadia about the Rambaldi's prophecy which dictates that two sisters will fight and only one will survive.
While Nadia is in a coma, Sark is taken into APO to help them infiltrate Cadmus Revolutionary Front and retrieve the bomb, but in return he demands to see Lauren's corpse. Nadia may be the only person with the intel they need to intercept the bomb, so Jack is forced to prematurely wake Nadia from her coma, endangering her life, which doesn't please Sloane when he finds out.
Dixon enlists Sydney to help him prove that Sloane is double-crossing the CIA and using APO to steel the Blackwell Index, a master blackmail list, and to reconstruct the Alliance. Meanwhile, Vaughn discovers something disturbing about his father when he visits his comatose uncle.
Jack kills an old friend who is poised to receive a biometrically targeted weapon. Sydney confronts the weapon and saves an innocent civilian, whose live she initially endangers. Vaughn uncovers more disturbing stories of his father, who was possibly a traitor.
Nadia puts her own life - as well Sydney's and Weiss's - in danger after failing to unveil her past through a dangerous criminal. Meanwhile, Vaughn finds a person who is somehow connected to his father and Nadia as well.
When a mission goes wrong, Sydney is attacked and placed in serious danger. Meanwhile, Dixon is exposed to a deadly pathogen released inside APO which is subsequently placed in lockdown. Marshall is the only one outside of APO able to go and save Sydney, assuming he can get to her before its too late.
Sydney and Vaughn risk their lives trying to find out the truth about Vaughn's father. Jack and Sloane's conspiring together against Sydney and Vaughn is revealed. Sydney and Jack travel to the Nightingale facility to shut it down, but Sydney becomes trapped in the room with the Nightingale device. Jack goes to extreme lengths to save her.
In an attempt to talk to Sydney, Katya Derevko deliberately poisons herself and is temporally taken out from her cell. She unsettles Sydney by telling her that someone framed her mother as a means of getting her killed. Meanwhile, Vaughn becomes a rogue agent by getting involved with the people who might know his father's whereabouts.
Sydney and Vaughn tell Jack about Sloane's alleged involvement in Vaughn's search for his father and Irina's contract on Sydney's life. After cornering Sloane, they both conclude that someone is framing him. The APO team set a trap to catch the fake Sloane, but Nadia fears that this pursuit may revive her father's past obsession – Rambaldi.
Nadia's former caretaker, Sophia, contacts Nadia and asks to meet her. She reveals that someone is trying to track Nadia down, so Sloane and Jack decide to tell their daughters the truth – Elena Derevko, the third and the cruelest of the Derevko sisters, has been surveilling both Sydney and Nadia for a decade. Meanwhile, Jack's doctor advises him to tell Sydney about his illness.
Jack's illness causes him to hallucinate about a cure. Sydney must recreate the time when Jack was working for the CIA and hid the only man who might be able to help him now. For this, Sydney must play her own mother. Meanwhile, Sophia moves in with Sydney and Nadia.
The APO team sets a trap in Paris that manages to snare the Sloane impostor. After Jack uncovers the origin of the Sloane clone, Marshall devises a way to shock him back into his own reality. But this technique poses a potential danger to the real Sloane.
After a tactical group infiltrates the DSR and steals Rambaldi artifacts, CIA director Hayden Chase discovers that the alarms at the DSR were disabled from Nadia's computer, allowing the raid to happen, and shows up at the apartment to question her. Soon Sloane and Jack arrive and suspect that Sophia, who had access to the computer while she was living with Syd and Nadia, is Elena Derevko.
Rambaldi's catastrophic endgame begins to fall into place as a giant version of the Mueller device is found floating over a city in Russia, driving the citizens mad. Sydney and Nadia discover Irina, whose death was faked, had been working to counter her sister's organization and prevent the Rambaldi endgame. They all work together to try to stop it.
Jack, Sydney, Irina, Vaughn and Nadia parachute into Sovogda. At APO, Marshall and Weiss use the Blackwell Index to blackmail the Russian minister into giving them the access codes to a Russian satellite. They learn that the Rambaldi device is broadcasting a frequency that physiologically alters people who drink it and it is irreversible. Elena learns of APO's arrival.
After learning that the man she has known as Michael Vaughn is under investigation and suspected of being a double agent, Sydney begins to question whether their business and personal relationship over the years had all been a lie. Meanwhile, because of Jack's past betrayal by Irina, he begins to worry that his daughter may suffer the same fate that he did.
Sydney teams up with Renée - a fugitive on the CIA's most wanted list -- to track down Vaughn's murderer before the killer can strike again. Meanwhile, Jack enlists a reluctant new agent, Thomas Grace, and Weiss struggles to decide whether or not to accept a promotion that would force him to leave his friends and colleagues.
Sydney is forced to partner on a mission with new APO agent Thomas Grace. They discover that Rachel Gibson -- a spy suspected of being involved in activities against the U.S. -- has something shockingly in common with Sydney. Meanwhile, Dixon must accompany Sloane, who's given a 48-hour pass from prison to acquire a possible cure for his daughter, Nadia.
When Gordon Dean discovers Rachel is still alive he captures Sydney while she is returning from a mission. He demands that Rachel should be returned to him but Sydney is reluctant to agree to his terms. However, if Sydney refuses she could face almost certain death. Meanwhile Sloane goes before a judge.
Sydney and Tom discover that Renée has stolen the cryo container, and soon find themselves under siege by a group of mercenaries who want the contents of the container. Meanwhile, Sloane takes matters into his own hands to get himself back into APO and continues his quest to find a cure for Nadia.
Rachel goes on her first mission while her family is placed in the witness protection program for their safety. Meanwhile APO sets up a trap using János Vak as bait which they hope will capture Dean, and they set Rachel the task of bringing him in.
Sydney and APO attempt to discover whom Gordon Dean is working for and what their end game is. Meanwhile, when the group, claiming to have a cure for his daughter Nadia, continues to play mind games with him, Sloane struggles for control.
Rachel is called on a mission when a Micropulse bomb explodes on a train. APO believes this explosion can lead to information about Prophet 5. Rachel is asked to go to Brazil and bug Basarov's computer but she runs into Sark in the process who seems to be doing exactly as she is.
Sydney teams up with Vaughn, or at least she believes that she does, after being kidnapped and being placed in a hypnotic state. What Sydney doesn't know is that the kidnapper is a very familiar face with an obscure interest in her unborn child.
Sydney sends a distress message so the APO team can locate her, but to retrieve it the team has to enter the CIA headquarters undetected. When they get trapped inside the building, they call upon an old friend to help them escape.
When Irina appears at Sydney's house, she persuades Jack and Sydney to go with her to Vancouver to retrieve The Horizon. which is being safely secured in a bank. While they try to get the item Peyton also tries to get it and all the action brings on Sydney's labor.
One month after the baby is born, Sydney is taking time off from work. Meanwhile, Kelly Peyton arranges for Anna Espinosa, Sydney's old enemy, to be released from prison and kidnap Will Tippin, who is still in the Witness Protection Program. The kidnapping is a ruse to draw Sydney away from her sabbatical.
While the gang starts to learn more about Prophet 5, Sloane is distressed to learn that the cure for Nadia that Prophet 5 gave him is just as likely to kill her as to save her. Meanwhile, Devlin returns, the search for Anna Espinosa continues, Rambaldi's prophetic Page 47 resurfaces, and Sydney offers Renée a job at APO.
Marshall reports to Jack that a microchip, found in Renée Rienne's body, is etched with the name 'Andre Micheaux'. Peyton tells Sloane that Sydney is being sent to Nepal to meet with someone regarding the chip. Sloane sends Anna, now Sydney's doppelgänger, to intercept. When Marshall discovers that the APO office is bugged, Jack frantically tries to reach Sydney to warn her before it is too late.
Sydney now posing as Anna, brings Peyton a microchip with a device hidden in it. Meanwhile Sloane finishes translating Page 47 and reports that only the Chosen One can complete the circle, which leads Sark and Sydney on a dangerous mission to a prison. Rachel finally discovers Tom's secret about what happened to his wife.
Sloane takes Marshall and Rachel hostage in order to discover a crucial clue to Rambaldi's ultimate endgame, as Sydney, Vaughn and APO race to stop him. In an effort to find the missing members, Jack contacts Marshall's wife Carrie and asks her to come in to help.
Kelly Peyton tells Sloane that she has made a deal for the Rambaldi Sphere with an ally in China. Sloane arranges for stolen missiles to be sent to Hong Kong. Sloane's plan is revealed to the APO members, who race to stop him before he can use the Rambaldi Sphere to put the plan in motion. Meanwhile Sydney has a long awaited confrontation with her mother.