Here's a basic rundown of the plot for 24: The Game:

From faqs.ign.com

*********************SPOILER ALERT***********************

CTU gets a lead by a caller that does not give his identity. He says that there is a ricin bomb at the harbor, so CTU sends in a team of agents lead by CTU Agent Jack Bauer. Jack commands team b to cover another entrance, so no one can escape. Doing so, team b commander trips a laser, resulting in an alarm going off. While the ship is on high alert, Jack heads in with a bomb team. While protecting his colleagues, he finds the bomb and the team defuses it.

He contacts Tony and tells him about his discovery.

Meanwhile, CTU Washington Agent Chase Edmunds contacts CTU Analyst Chloe O'Brian. His phone call is being traced, so the terrorists try to contact a man named Peter Madsen in LA. Chase locks town the facility and kills all of the
terrorists.

Tony, Jack, and Michelle go on many pointless leads that sums up nothing. Then Kim Bauer enters CTU, anticipating her job as an analyst in CTU. When she enters, Peter Madsen and his squadron of terrorists invade CTU. Tony is away
following a lead, so Michelle escorts Kim to M8, a panic room. When they arrive, Kim goes in but Michelle is held captive. Tony tells Kim to lockdown CTU, while he and Jack plot a way into CTU undetected. She is caught after
locking down CTU and held captive.

Jack takes out Peter's chopper on the CTU rooftop, but Madsen escapes with Kim by vehicle. With him is Agent Edmunds, now in LA after a flight for Washington.

Jack later gets Kim back from Madsen's facility near a drainage ditch. When he is contacted by Tony, Jack learns of Madsen's next terrorist plot.

Jack is at a bomb site underground, where Madsen is plotting to start an earthquake by blowing up a bomb in an underground hotspot. Jack and a bomb expert fail to defuse it, resulting in an earthquake. He must now return to CTU
under orders by Division chief Ryan Chappele. But on the way he gets a phone call from Kate Warner.

Kate is trapped in a subway station. Madsen soon kidnaps her to lure Jack to him. Jack follows him and chases him in a car throughout a devastated LA, from the earthquake. Madsen soon escapes in a chopper.

Tony gets a lead from the California governor James Radford's assistant. When he gets to the meeting place, he is ambushed by a chopper. Radford's assistant is brutally killed. She tells him to check the governor's safe.

Tony finds the safe and Radford at the State house. Radford is assassinated by Mandy, the assassin that attempted to kill Palmer in Season 2. He finds evidence that proves the Governor guilty of terrorism.

Jack and Chase team up at a military base and take back a stolen document. They learn that they kidnapped Kate to blackmail Bob Warner to allow them to ship out nuclear contraband without trouble from port authority. Jack and Chase take down Madsen and foil the terrorist plot.

Tony heads to the docks by chopper to tell Jack of Kate's location. They head to a in the ocean. After Chase takes out terrorists so Jack can enter the area, Jack finds Kate held hostage by a terrorist. Jack gets shot in the stomach, but kills the terrorists. Kate and Jack leave the yacht, with Tony and Chase in the chopper. It's now sunrise.