Chicago P.d. - Season 4 -

The season's narrative is framed by accountability and the personal cost of life in the Intelligence Unit:

Season 4 featured several "One Chicago" crossovers that connected the unit to Chicago Fire and Chicago Med : Chicago P.D. - Season 4

A crossover with Chicago Fire (Season 5, Ep. 9) where Kelly Severide is suspected of vehicular manslaughter. The season's narrative is framed by accountability and

In "All Cylinders Firing," Desk Sergeant Trudy Platt (Amy Morton) is brutally attacked outside her father's home, leading to a personal and harrowing investigation into her past. Chicago P.D. - Season 4

Season 4 marked the end of an era for two of the show's original leads and introduced a future mainstay: