Season 5

Season 5 debuted in the United States on Monday, January 16, 2006 on Fox, and debuted in the United Kingdom on Sunday, February 12, 2006 on Sky One.

Season 5 had the highest audience ratings so far. The show improved its overall audience by 14 percent over its fourth season and by 12 percent in the age 18-49 demographic, averaging a total audience of 13.8 million, therefore ranking #23 for the 2005-2006 Nielsen TV Season.

Fox announced plans to re-air Season 5 on Fridays during the summer, starting on June 16, 2006 and showing two episodes per week.

Summary
Eighteen months after faking his death, Jack Bauer is living under the alias Frank Flynn and renting a room from a single mother and her son. Soon after Former President David Palmer is assassinated, Jack gets a frantic call for help from Chloe O'Brian and he realizes that the four people who know he is still alive are being targeted. Jack returns to CTU Los Angeles to figure out who is really behind the assassination of David Palmer, and uncovers a plot involving deadly nerve gas and people inside President Logan's administration. As Jack searches for the people involved and tries to stop the nerve gas from being released, he discovers that the conspiracy goes higher than anyone could have ever imagined.

The series can be divided into several acts:
 * A group of Russian terrorists use a series of assassinations and hijackings as a way to obtain twenty hidden nerve gas canisters. Although the terrorists were supposed to succumb to a controversial sting operation, they manage release the canisters at several key locations &mdash; including CTU &mdash; before releasing all but one canister into the LA gas supply. This attack is foiled before the gas spreads into the system.
 * Throughout the night, the politicians and power brokers behind the conspiracy initiate damage control because Jack Bauer discovers some incriminating evidence against one of them. Meanwhile, tensions rise at the President's retreat as the damage control spirals out of control.
 * The terrorists attempt to launch their final attack by using the final nerve gas canister to seize a powerful weapon. The attack is thwarted by Jack and Christopher Henderson. Afterward, Jack manages to incriminate the kingpin of the original conspiracy, but he is apprehended by a forgotten factor.

Main Cast

 * Kiefer Sutherland as Jack Bauer
 * Kim Raver as Audrey Raines
 * Mary Lynn Rajskub as Chloe O'Brian
 * Carlos Bernard as Tony Almeida
 * Gregory Itzin as President Charles Logan
 * James Morrison as Bill Buchanan
 * Roger Cross as Curtis Manning
 * Louis Lombardi as Edgar Stiles
 * and Jean Smart as First Lady Martha Logan