The detectives get a break in a case involving a police officer suspected of committing murder.
Agent Doggett awakens in a corrupt and violent Mexican town with no memory of his true identity.
The squad fears terrorism after a judge and a lawyer receive letters filled with white powder; Internal affairs puts the squeeze on Clark to rat out Andy after the death of a hooker informant.; Jones gets back into the dating pool with another co-worker.
Injured Steve and Jesse help evacuate hospital bombing survivors, while Mark works heroically to save Amanda.
Sam (Scott Bakula) leaps into the body of a piano-lounge player who finds himself on the run, together with his former music partner, from a mob killer who wants the lounge lizard eliminated.
