Johnny goes undercover to stop a gang war; Jakes and Charlie set out to take over Germaine's business; and Mike begins to piece together Briggs' plan.

The feud between the Sarkissians and a local gang heats up; Briggs' motives are revealed; and Mike hunts for the sarin gas.

The agents struggle in the aftermath of the gang war while Briggs tracks down a loose end in order to bring Ari Adamian to justice.