24: The Game takes place 6 months after Day 2 and 2 and a half years before Day 3. In a similar way to the TV series, it can be split up into three sections or chapters. Section one revolves around an attack on Jim Prescott, while section two covers an attack on the Counter Terrorist Unit (CTU). Section three covers a major terrorist attack and attempt to gain access to nuclear weapons. A large number of characters from seasons two and three feature in 24: The Game, with each using the original actor's likeness and voice acting. Main characters returning include Jack Bauer, Kimberly "Kim" Bauer, Tony Almeida, Michelle Dessler, Chase Edmunds, David Palmer, Max, Kate Warner, and Ryan Chappelle, with Peter Madsen being voiced by Christian Kane.
The game begins with Jack Bauer waiting outside a ship in the Los Angeles harbor where terrorists are going to release a ricin bomb in the water supply. A CTU team member triggers an alarm causing Jack and his team to storm the ship, discovering the whole ship's crew dead in a cargo hold. He later learns of an assassination attempt on Vice President Prescott through undercover agent Chase Edmunds. Foiling the attack, Jack discovers that the mastermind behind the attempt is an enemy from his past known as Peter Madsen.
A Sarin gas attack on LA Metro station lures CTU agents away from their headquarters. While distracted, terrorists activate an EMP, attacking and taking over the CTU LA main building, holding the staff members hostage. The terrorists execute these hostages, including data analyst Sean Walker and eventually escape with a stolen hard drive. Jack runs into Peter Madsen, who has kidnapped Jack's daughter, Kim Bauer, forcing Jack to do "errands" for the terrorist cell. One of these errands is to sneak into a NSA building and retrieve confidential data for the terrorists. Jack manages to find and rescue Kim and recover the stolen hard drive with the help of undercover agent Chase Edmunds.
A major earthquake occurs in Los Angeles, caused by terrorists detonating explosives at focal points (places where fault lines intersect). Kate Warner is also kidnapped by the terrorist cell, along with Governor James Radford who is kidnapped for assassination but is then rescued by the CTU. A conspiracy involving Radford in the day's attacks is uncovered by the CTU and Radford is killed by the terrorist cell because he attempts to back out. Fort Lesker, U.S. Military base and the epicenter of the earthquakes, is attacked and taken over by terrorists, who then begin stealing weapons-grade plutonium before attempting to smuggle the weapons out of the U.S. to the Middle East. Kate Warner's father is forced to aid the terrorists by helping them smuggle the weapons with his customs passes. Jack finally kills Madsen when he tries to escape by shooting his speedboat with an M-80 assault rifle, causing it to explode. He also kills Max, who was holding Kate Warner hostage, saving her life but in doing so Max manages to shoot Jack once in the stomach before dying. As a result, Chase Edmunds takes Jack to the hospital via helicopter.