Guilt-ridden Officer Nick Barron returns to work following a deadly shooting. Ben Chartier's transfer to Station 19 from the rural police force turns rocky after a split-second decision triggers an internal investigation.

A showdown between rival street gangs goes terribly wrong, leaving Ben's life in danger. Squad 19 gathers at Marie's for the Sergeant's party. Isabelle discovers Nick may have feelings for someone else.

The first of the month brings 'Welfare Day' to 19. Nick and Ben handle a dangerous array of belligerent civilians. The day caps off with a cataclysmic domestic disturbance.

Tyler botches a takedown of a gang of rapists nearly costing Nick's life, leaving Ben to question Tyler's fitness on the job. Nick brings Harvey to Houle's BBQ, which goes crudely awry.

Nick butts heads with his nemesis J.M. when they are assigned patrol together. Beatrice embarks on a new romance.

A cover-up comes back to haunt Nick and Ben, pitting them against Gendron. Nick's frustrations mount when Ben encroaches on his personal life.