The city is on high alert after multiple mail bombs target a criminal defense attorney and an insurance adjuster. The team eventually identifies the culprit as , the son of Victor Costas—a man Bobby Nash had arrested for arson years prior.
Beyond the action, the finale focuses heavily on the personal lives of the first responders: [S2E18] This Life We Choose
: Freddie detonates a bomb on one of the 118’s fire trucks, leaving Buck pinned and severely injured under the vehicle. The city is on high alert after multiple