Chicago Fire (2012)

S04E01 Let It Burn

While working undercover to dismantle a trafficking operation at Nesbitt's club, Casey finds himself in a perilous predicament. The squad's frequent staff changes lead to an unexpected challenge for Severide. Meanwhile, Dawson realizes that her life is on the brink of transformation. A new recruit arrives and leaves a striking first impression. In the community, residents unite to take a stand against a drug den that has taken root in their area.