An arsonist sets a fire at a car dealership that kills a sales person. The name of an extremist environmental group is spray-painted on the scene, but the group denies involvement. It becomes Don's task to determine whether the group or someone else is responsible. Charlie is called in to help figure out if there is a pattern to the fires that would help provide a profile of the arsonist.

Two rock climbers in possession of a large stolen diamond are killed, and Don and the team hunt for the murderers; Charlie considers whether he should have his FBI clearance reinstated.