Jack and Hector both search for Kyle, while Chase finds himself out of action at CTU. Wayne and Palmer argue over the implications of Anne's past, while Ramon takes out one of his opponents in a surprise move. Tony leads an operation to get Kyle, but tragedy strikes when Salazar's man gets there first.

The episode was rated 7.90 from 503 votes.

Jack's efforts to break Ramon out of prison go awry when they are captured by a group of inmates during the riot. Chloe unwittingly stumbles on to Jack's drug problem and she is forced to reveal his secret to Kim and Michelle. Palmer begins his debate with Keeler, while Kyle prepares to sacrifice himself to save Linda.

The episode was rated 7.92 from 479 votes.

Saunders begins making demands on the President. He forces Palmer to hold a strange press conference and then orders the death of the CTU agent who can trace him. Jack learns of a woman who can lead him to Saunders, but a surprise attack shifts the balance of power. As Gael's symptoms get worse, Michelle devises a way to relieve the suffering of the victims at the hotel.

The episode was rated 7.95 from 438 votes.

Jack attempts to use Saunders' daughter as leverage to gain control of the virus, while Palmer must deal with the discontented press. Michelle gets the results of her test, while Adam finds that the virus has struck too close to home. Tony finds himself compromised when Saunders exploits his only weakness.

The episode was rated 7.95 from 425 votes.

Jack and Ramon struggle to evade the authorities, while Palmer must shut the debate down because of the prison break. Kim accidentally stumbles on to Gael's secret communications, but she isn't able to warn Michelle in time. The Singer family learns a startling piece of news about Kyle's health.

The episode was rated 7.95 from 459 votes.

Jack reluctantly works with Kim on an under-cover job that may help them gain an advantage over Saunders. Palmer informs his cabinet of the crisis, while Saunders makes yet another demand. Chase tracks down the man who left the hotel and learns that the virus is spreading to the general public.

The episode was rated 7.99 from 432 votes.

Chappelle threatens to pull Jack from the investigation for killing a material witness, but Jack persuades him to hold off when they find a fresh lead on Amador's whereabouts. Amador and Alvers meet with the man who is planning to unleash the virus in LA within the hour. Michelle and Gael locate the target area, but things really hit the fan when they attempt to capture Alvers in the process of releasing the virus. Wayne argues with Sherry over the consequences of Milliken's death as the police turn up the heat on Julia.

The episode was rated 8.00 from 450 votes.

Tony works to free Jane from CTU before Saunders can harm Michelle, but Chloe and Jack become suspicious of his activities. Sherry meets with Palmer's political rival and proposes a deal to blackmail him.

The episode was rated 8.02 from 429 votes.

Tony interrogates Nina about Alvers' location, while Chappelle orders Jack to undergo a medical examination in light of his drug use. Kim and Chase have a conversation about the baby. Palmer confronts Sherry about Alan Milliken's death, while Julia begs Wayne for help.

The episode was rated 8.06 from 438 votes.

Ramon holds Jack hostage as he flies to Mexico. Ramon plans to kill Jack, but Jack manages to hold him at bay until the plane lands. Ramon then learns that Jack and Hector are working together to break him out of prison. Gael is captured while trying to escape from CTU. Chappelle interrogates Gael but is interrupted by Tony, who claims that Gael is part of a bigger plan. Anne is given a chance to clear Palmer's name, while Chase heads for Mexico to rescue Jack.

The episode was rated 8.09 from 466 votes.

Jack and Chase track Amador in the hopes that he can lead them to the man behind the virus attack. Michelle faces a mob riot when the hotel is quarantined. Sherry extorts Palmer, forcing him to manufacture her alibi for the police.

The episode was rated 8.09 from 430 votes.

Jack pushes the envelope in an attempt to force Saunders to disclose the location of the missing vials. Sherry meets with David to discuss her terms, while Wayne breaks into her home to find the incriminating evidence. Tony finds himself facing a harsh penalty because of his efforts to save Michelle.

The episode was rated 8.13 from 425 votes.

Jack and Tony clash as the time for the hostage exchange draws near. Keeler meets with Palmer and demands his resignation, while Wayne begins a secret operation against Sherry.

The episode was rated 8.13 from 429 votes.

Jack and Chase race against time to capture Saunders before the deadline, while Chappelle plans an escape. Michelle begins a frantic search when she learns that an infected hotel guest may have slipped through her fingers.

The episode was rated 8.17 from 439 votes.

Jack and Chase must make a powerful sacrifice when dealing with the virus. Tony is able to help Jack one last time before he is taken into custody, while an angry victim seeks vengeance on Saunders. Palmer makes a surprising career choice in the wake of Sherry's death.

The episode was rated 8.33 from 444 votes.