Four more “suitcase nukes” are out there, and Jack’s only lead takes him to the home of his brother.

While Jack has problems with Curtis, CTU discovers a nuclear threat and raids a terrorist warehouse, and a shocking explosion shakes LA.

Jack and former terrorist leader turned peacemaker, Hamri Al-Assad, track a suspicious man to a self-storage facility.

Can Jack and an unlikely ally stop a suicide bomber and track the architect of these acts of terror?

A new U.S. President has negotiated Jack’s release from a Chinese prison so Jack can stop a series of terror attacks… with his life.

Jack takes his fight directly to the President as he attempts to force a confession from him that will prove his involvement in the day’s events. Martha vents her hatred for her husband in front of the press as Logan gives a eulogy over Palmer’s body. Jack and Audrey share a tender moment when it seems the crisis has subsided, but Jack finds that his problems have only begun as his past catches up with him.

Jack and Henderson wage an assault on the submarine as Bierko prepares to launch an attack against L.A. Chloe brings in someone from her past to aid her. Martha and Aaron enlist Mike’s help in their plans to expose Logan.

Bierko escapes from the transport taking him to Division and uses his last canister of nerve gas for a surprise strike. Jack is forced to work with Henderson to find Bierko, but Henderson wants something in return. Logan takes drastic steps to deal with Aaron when he won’t go along with the cover-up.

Jack searches for a safe place to land the plane when Logan gives orders to shoot it down. Hayes readies Bierko for a transfer to a secure facility, while Audrey receives some good news about her father. Logan becomes desperate as his plans start to unravel, but an unexpected ally at CTU turns the tables in his favor.

After stowing away aboard the flight containing Henderson’s contact and the incriminating recording, Jack finds himself having to deal with a pilot who refuses to cooperate.

Martha begins to break down, and Mike becomes suspicious of what she is hiding from him, while Logan tries to calm his financial backers.

Jack captures Henderson and attempts to force him to hand over the recording, but Henderson targets Heller to buy himself more time. Logan confesses his involvement in Palmer’s assassination to a distraught Martha. Miles traces Chloe to Buchanan’s home, but Hayes finds herself questioning Logan’s motives as CTU closes in.

Jack shows Heller the incriminating recording in the hopes that he will help them take down Logan, but Heller has plans of his own that will save face for the presidency. Miles tricks Chloe into leading CTU to Jack and Audrey. Mike and Martha both become more suspicious of Logan’s actions, while Heller confronts the president with an ultimatum.

Jack and Wayne locate a recording that definitively proves Logan’s involvement in the terrorist conspiracy, but Henderson corners them in the hopes of destroying the incriminating tape.

Logan tries to cover his tracks by issuing a warrant for Jack’s arrest.

Audrey contacts her father for help, while Chloe gives her cover while helping Jack evade CTU.

Jack and Wayne locate a source inside Logan’s administration who has information on Palmer’s assassination. But things get complicated when they learn that Henderson is using leverage to keep her silent.

Audrey is forced to choose between Chloe and Buchanan as Homeland Security begins to absorb CTU.

Jack pushes Audrey for answers when evidence indicates that she may be involved with the terrorists.

Wayne and Aaron flee from a group of gunmen who have orders from Henderson to kill them.

Bierko and his men gain access to a natural gas plant, where they plan to distribute the nerve gas throughout L.A.

Jack bargains with a German intelligence agent in order to find the woman who can lead him to Bierko.

Buchanan chafes against the new chain of command as Homeland Security prepares to take over CTU operations.

Aaron receives a request for a secret meeting from Wayne Palmer, as Logan implements martial law in L.A.

Jack and Lynn must take action when they discover that the nerve gas is breaking through the protective seals that are keeping the CTU survivors alive.

Chloe wrestles with her grief over Edgar’s death, while Tony contemplates revenge against Henderson.

Martha bolster’s Logan’s spirit as he wavers under more political pressure from Gardner.

Jack takes Henderson to CTU for questioning. Once there, he faces an unhappy reunion with his daughter, Kim.

Mike appeals to Martha for help as Logan faces pressure from his Vice-President to declare martial law on L.A.

Lynn connects the theft of his keycard to an impending strike on CTU, but his warning comes too late to stop a terrorist from infiltrating the building.

Jack interrogates Henderson’s wife about her husband’s connection to the terrorists.

Lynn begs his sister to return his stolen keycard, while Tony regains consciousness and learns of Michelle’s fate.

Martha gives Logan the cold shoulder, while Curtis tracks another nerve gas attack to a local hospital.

Logan wrestles with his conscience when he learns that Martha is riding in the motorcade with the Suvarovs.

Audrey convinces Curtis to take action as Lynn continues to abuse his authority.

Jack learns that an ex CTU agent, Christopher Henderson, works for a company which is connected with the nerve gas.

Lynn orders Curtis to take Jack into custody for violating presidential orders, but Jack breaks away from Curtis when Nathanson contacts him through Audrey and offers information on the location of the nerve gas.

Lynn begins to unleash on his coworkers as he discovers that they may be working against him to aid Jack.

The head of the terrorists makes a demand on Logan, and Martha takes a dangerous step to get her husband’s attention.

Jack poses as Rossler and manages to trace one of the canisters of nerve gas, but he goes against orders from the president when the terrorists target a shopping mall.

Logan and Martha quarrel when she learns of her husband’s intention to cover up the real reason for Walt’s suicide.

Jack tracks down a man who has a connection to the terrorists. Logan is forced to grant him immunity in exchange for information on their whereabouts.

Mike and Martha argue over Logan’s public response to Walt’s involvement with the Russians.

Lynn is drawn away from his post by a personal crisis as the terrorists come closer to striking against the U.S.

Jack contacts Mike and asks for a secret meeting in hopes of gathering evidence against Walt.

Martha begs Aaron for help, while a desperate Walt tries to force Logan to aid him in his complicity with the terrorists.

Buchanan butts heads with Lynn over a decision to violate the president’s orders, while the Russians attempt to escape with the nerve gas.

Jack returns to CTU and has an emotional reunion with Audrey, while Curtis tracks the Russians and the stolen nerve gas.

Walt sends in a hit man to silence Jack.

Chloe discovers that Spencer has his own agenda at CTU.

Walt convinces Logan to have Martha institutionalized when she tells them of the attack on her.

Jack is captured by the terrorists, who use Derek as leverage to force him to compromise CTU’s assault operation.

Logan refuses to give into the terrorist demands as the time of the co-signing of the treaty draws near. Martha tries to tell her husband of the evidence she uncovered about her phone call with Palmer, but Walt interferes with her efforts.

A new representative from District arrives at CTU and begins to undermine Buchanan’s authority.

Jack conceals himself inside the airport hanger and surveys the Russian separatists, feeding information to Curtis and his assault team.

The terrorists begin executing hostages in an attempt to make Logan cave into their demands.

Martha discovers that all traces of her conversation with Palmer may not have been erased.

Jack and Chloe infiltrate Wayne Palmer’s penthouse where David Palmer was assassinated, in the hopes of finding a clue to his murder. Jack convinces Wayne to cooperate and finds some information in Palmer’s memoirs that leads him to the airport where the Russian president is about to land.

CTU and Secret Service attempt to capture Jack, but they only find Chloe as Jack and Derek slip through their grasp.

Martha tries to convince her husband that she received an important phone call from Palmer the night before his death, but a tape of their conversation seems to contradict her claims.

Jack goes to the airport to find a lead, but a group of renegade Russian terrorists take hostages, including Derek, before he can act.

18 months have passed since the events of Day 4. With the exception of David Palmer, Tony Almeida, Michelle Dessler and Chloe O’Brian, the world believes that Jack Bauer is dead. Jack is living near L.A. under the name of Frank Flynn, working on an oil rig and living with Diane Huxley and her teenage son, Derek.

In L.A., David Palmer is visiting his brother Wayne, when he is killed by an assassin’s bullet. As CTU scrambles to gather more information, an exploding car bomb kills Michelle and injures Tony. Chloe is also pursued by an unknown figure, but she eludes him and manages to contact Jack for help.

President Charles Logan and his wife Martha are visiting L.A. and are planning to sign an important arms treaty with the president of Russia. Martha seems to be unstable and is badly shaken by the news of Palmer’s murder. Logan refuses to heed CTU’s warnings of possible danger and call off the summit.

Jack is forced to take Derek along for the ride as he meets with Chloe and fights off a group of men who want him killed. He forces one of the men to confess that Jack has been deliberately framed for the murders of Palmer and Michelle.

As the missile speeds toward its destination, Mandy cuts a deal with Jack and the President to give up Marwan’s location in exchange for a full pardon on all of her crimes.

Tony and Michelle share a happy reunion, but Jack finds his relationship with Audrey shattered as she makes her feelings known.

Logan’s advisor suggests a drastic course of action when the Chinese government demands that Jack be handed over to them for trial. Palmer tries desperately to warn Jack of the danger against him.

Jack’s life changes forever as Tony, Michelle and Chloe help him to evade the trap set for him by Secret Service.

Mandy uses Tony as leverage to try to force Michelle to aid in her escape.

A Chinese security operative captures and interrogates one of the CTU agents involved in the raid on the embassy.

Palmer and Logan argue over the option of evacuating all major cities that may be targets for the missile.

Jack finds that his efforts to bargain with Marwan for the location of the missile strike are futile.

Heller pushes his son for information when CTU discovers that he may have had contact with Marwan before the attacks.

Logan finds himself in the middle of a power struggle between Palmer and the ambitious Speaker of the House.

Tony and Michelle explore their rekindled passion for each other, but their hopes for the future may be short-lived when a familiar player enters the game and takes a hostage.

CTU scrambles to forge an alibi when a Chinese representative produces evidence of American involvement in the raid on their embassy.

Audrey gives Jack the cold shoulder, while Palmer and Logan clash over the consequences of Palmer’s decisions.

Jack and Curtis close in on Marwan as the countdown for the missile launch moves ahead.

After Logan authorizes Palmer to take charge of the crisis, Palmer sanctions Jack and Curtis to infiltrate the Chinese Embassy on a covert operation to capture a suspect.

Tony and Michelle continue to bump into each other’s personal lives, while Buchanan expresses anger at being kept out of the mission.

Jack faces Audrey’s wrath when a medical dilemma places Paul’s life in jeopardy.

Chloe is unexpectedly thrust into fieldwork when a woman reports that her boyfriend may be part of the terrorist conspiracy.

Jack and Curtis find their latest efforts to trap Marwan thwarted by the Secret Service, who have orders to arrest Jack for insubordination.

Mike calls on ex-President David Palmer for help as Logan continues to display a lack of leadership.

Curtis brings in a suspect who has critical information about Marwan’s next strike. Michelle orders Curtis to use harsh methods to interrogate the suspect, but things get complicated when Marwan sends a lawyer to defend his rights.

Logan’s advisors begin to worry as he continues to exhibit fear in the face of the ongoing terrorist threat.

Mike pushes for the Vice-President to be sworn into office as the White House waits for news of Keeler’s fate.

Two innocent bystanders are dragged into the fight as Jack and Marwan both pursue a briefcase that contains the launch codes for America’s nuclear arsenal.

CTU raids Marwan’s hideout, but he manages to slip through their fingers. Luckily, Jack locates a lead that may help him identify Marwan’s next target.

Tony becomes suspicious of Michelle’s personal life, while Audrey reunites with Paul and learns the extent of his injuries.

Anderson closes in on his quarry, as President Keeler searches for words that will comfort the American public.

Marwan decides to trade Jack for Behrooz in hopes of distracting CTU from his real objective.

Tony and Michelle weigh the consequences of the trade, while Curtis reluctantly interrogates Behrooz in order to learn more about Marwan.

Jack learns the identity of a man who may be able to lead him to Marwan. He forces Dina to help him in a mock hostage situation that will get him close to the suspect.

Michelle calls on Chloe for help when Edgar begins to crack under pressure. Meanwhile, Audrey stands by as a gravely wounded Paul is taken into surgery.

Marwan’s plan continues as his henchman uses an unwilling pilot to gain access to an airfield.