Darwyn Al-Sayeed 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 decide to pose as Iraqi insurgents-in-training in order to infiltrate and take over a secure warehouse as a new base of operations for Youmid Din.
Darwyn becomes friends with a pesticide plant worker so he can purchase some of his company’s product under the table for the Cell. Meanwhile, the members are all dealing with personal conflicts of their own.
An Afghan boy comes to the warehouse looking for training as a jihad and Darwyn decides to introduce him to a more moderate brand of Islam in hopes of steering him away from terrorism.
The Cell purchases some explosives from a white supremacist militia. Also, 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 Youmud Din "Judgment Day" as the FBI prepares to stop them, not knowing that, due to a misunderstanding of the Arabic calendar, the attack will proceed one day earlier than they think it will.
The cell hijacks a chemical truck in preparation for Youmud Din "Judgment Day" as the FBI prepares to stop them, not knowing that, due to a misunderstanding of the Arabic calendar, the attack will proceed one day earlier than they think it will.
An American Muslim and FBI agent, scheduled to begin a stint as a teacher at Quantico, must first check out a terror suspect; the CIA grills former cell leader Farik.
Darwyn experiences problems on two fronts: as new leader of the cell, and with his new FBI case agent, whose inexperience in the field is a concern. The cell's first order of business is to steal a surface-to-air missile from a former arms dealer in Pakistan; Farik's interrogators turn up the pressure; Ilija has a plan to slip into Canada.
Unable to break Farik, American intelligence sends him to Saudi Arabia, where torture methods are stepped up; terrorist leaders order Darwyn to secure nuclear material, but his new FBI boss refuses to help; Ilija makes it into Canada, but must clear up loose ends before he goes back to Europe.
Escapee Farik finds refuge in a safe house in the city of Najran; Darwyn risks blowing his cover to keep a vengeful member of his cell from killing a televangelist; Ilija is guillt-stricken about having to kill a woman to facilitate his escape from Canada.
Darwyn and his estranged father have an uncomfortable reunion; Salim wrestles with his sexual identity; Ilija struggles to make it back to Sarajevo for a confrontation with his troubled past; Darwyn learns about Farik's special shipment to L.A. and attempts to intercept.
A new terrorist leader takes over the planned nuclear attack on Los Angeles and keeps Darwyn in the dark about the specifics; Mina goes on a mission that endangers Gayle; in Yemen, Farik turns the tables on an idealistic American philanthropist; Ilija's Bosnian homecoming is a disappointment.