Darwyn Al-Hakim is a Muslim ex-con who has just been released from prison and finds his way to an Islamic extremist named Farik, who recruits him to join a terrorist sleeper cell planning an attack in Los Angeles.

Farik and Ilija receive a deadly biological anthrax shipment and prepare for an attack inside a Los Angeles shopping mall. Darwyn's supervisor Ray Fuller become suspicious about the disappearance of a cell member.

Farik, Darwyn and Christian cross the U.S.-Mexico border at Tijuana to find out why the cell's pipeline of mob funds has suddenly gone dry.

Farik dispatches a biochemical student on a flight to Vancouver, Canada, to drive a shipment of real anthrax across the Canadian border and down to Los Angeles.

The cell members pose as Iraqi insurgents-in-training in order to infiltrate and take over a secure warehouse as a new base of operations for Youmud Din ("Judgment Day").

When an Afghan boy arrives at the warehouse looking for training as a jihadi, Darwyn introduces him to a more moderate brand of Islam in hopes of steering him away from terrorism.

The cell buys explosives from a white supremacist militia while Darwyn's new handler, Patrice Serxner, tries to prevent the LAPD from blowing his cover in a conflicting investigation.

The cell hijacks a chemical truck in preparation for Judgment Day, as Farik spends a last night with and bids farewell to his wife, and the FBI prepares to stop the attack.

Judgement Day has arrived and Fariq isn't yet out of surprises. A surprise diversion proves effective in allowing the cell to escape their surveilance. A quick thinking Darwyn leaves a clue that will hopefully lead the FBI to the target location in time.