24 (season 1) (2001)

Season 1 starts and ends at 12:00 a.m. PST. The first half of the season centers on the efforts of a terrorist cell led by Ira Gaines to assassinate presidential candidate David Palmer. They kidnap Jack Bauer's wife and daughter in order to force him to aid in the assassination and take the fall for Palmer's death. Jack eventually defeats this cell in the process of saving his wife and daughter, but this only leads to information about a second group of terrorists who had employed the first cell. The second cell is led by those ultimately responsible for the day's events: Andre and Alexis Drazen.

Two years prior to this day, Jack Bauer was sent as part of a classified team to Kosovo on the orders of a secret Congressional panel headed by David Palmer to kill Victor Drazen, Slobodan Milošević's "shadow." In order to keep Operation Nightfall totally secret, the panel never met nor knew the team of operatives, and nor did the team know the panel. Therefore, Palmer and Bauer never knew about each other. The Drazens found out about both Palmer's and Bauer's involvement in their father's death , and the whole assassination plot had been a means to get back at them—Palmer would be dead, Jack would be imprisoned for the assassination, and his family would be killed.

During the last few episodes, the plot twists revealed many surprises. It was revealed that Bauer's team had only killed Drazen's body double. Drazen's wife and daughter, however, were inadvertently killed, prompting the "eye for an eye" aspect of the plot: as Drazen's wife and daughter died, so would Bauer's wife and daughter. Viewers also discovered that the real Victor Drazen is a top secret, unofficial prisoner of the US government, and the Drazens' primary goal was to free Victor Drazen.

Eventually, in order to satisfy the Drazens, Palmer's death is faked. The Drazens recapture Bauer's daughter Kim and offer to exchange her life for Bauer's. However, Kim escapes and the Drazens soon learn that Palmer is still alive. With time running out on his chance to escape before he is recaptured, in desperation, the freed Victor Drazen tells his mole inside CTU, who is revealed to be Nina Myers, to call Bauer and tell him that his daughter is dead and that the Coast Guard has found her body. Drazen knows that a grieving Jack will attack him, and he believes he, his son Andre Drazen and their henchmen can kill Jack. Nina is reluctant, knowing that if Drazen's plan fails, Jack will very quickly learn that Kim is not dead and that as Nina had lied to him she must be the mole. However Nina does indeed tell the lie to Jack.

Drazen's plot backfires rather spectacularly, as an enraged Jack kills Drazen's son and guards, and in the process corners Victor Drazen before killing him, after both have exchanged fire in a shootout. Afterwards, Jack Bauer speaks with a member of the Coast Guard to arrange to claim his daughter's body. The Coast Guard informs Bauer that they did not find a body that night. Bauer realizes that Nina Myers is the mole. He calls George Mason and tells him to detain Myers, but Myers, who heard that Bauer had survived, was already preparing for exfiltration by erasing all the incriminating information of herself on CTU's computer. Bauer's wife, Teri, is confused about the events surrounding Jack's attempt to rescue their daughter, and looks for Myers, whom she trusts. Teri realizes that Myers is the mole, however, and Myers ties her to a chair. Jack comes to CTU and lets the agents take Myers into custody . He then discovers his wife's body in the chair with a fatal gunshot wound in her chest. The season ends with Jack cradling his dying wife in his arms, while he constantly tells her body he is sorry.

The season has a dramatic and unexpected ending: the death of Teri Bauer. Many fans were dismayed by this sudden plot twist, while others applauded 24's genre-defying willingness to unexpectedly kill major characters. The producers also filmed an alternate ending in which Teri, Kim, and Jack are reunited. However, they eventually decided to go with the death of Teri Bauer as the climax of season one. The alternate ending is available on the DVD boxed set for the season.