Jack is back, this time in New York City spending time with his granddaughter. However, when a former contact comes to him with vital information on an upcoming terrorist assassination attempt, Jack has no choice but to become involved and take the man to CTU. But to get to CTU, they first need to survive a whole bunch of terrorists all trying to kill them. Meanwhile, Chloe struggles to settle in at her new position at the upgraded CTU, and President Allison Taylor negotiates with Middle Eastern leader Omar Hassan over weapons inspections... unaware that Hassan is the assassins' target. Also, a journalist named Meredith Reed is suspected to have direct ties with the on-going terrorist crisis.

Jack Bauer becomes further involved in preventing an assassination attempt on visiting president Omar Hassan. As the crisis continues to escalate, the crew at the newly upgraded CTU is challenged by some unexpected complicated circumstances. Meanwhile, tensions run high when an explosive event jeopardizes international security.

Four explosive hours after being unwillingly drawn back into action, Jack Bauer reteams with a risky Renee Walker to track some very dangerous leads. Meanwhile, back at CTU, a desperate Dana Walsh faces tense and untimely circumstances, and emotions escalate when President Taylor learns of a larger looming threat that jeopardizes the peace accord with President Hassan.

Undercover Agent Renee Walker confronts her painful past when attempting to broker a deal with a ruthless, but very well-connected German arms dealer. When CTU shifts its focus from the perilous circumstances surrounding Jack and Renee, lead analyst Dana Walsh comes up with a plan to quell her situation and Chloe O'Brian puts Arlo Glass in his place. As Jack and Renee’s undercover mission takes unexpected turns, the Hassan family turmoil has President Taylor reeling as the peace agreement is jeopardized.

President Taylor's vision of global peace has been foiled over the last 13 hellish hours, and the situation worsens when the imminent threat of mass destruction clarifies. As her idealistic nature becomes a point of contention, she tasks Jack Bauer with a crucial mission, and advisor Ethan Kanin returns in the heart-stopping.