The fourth season of Chicago Fire, an American drama television series with executive producer Dick Wolf, and producers Derek Haas, Michael Brandt, and Matt Olmstead, was ordered on February 5, 2015, by NBC,[1] and premiered on October 13, 2015, and concluded on May 17, 2016.

[3] The show follows the lives of the firefighters and paramedics working at the Chicago Fire Department at the firehouse of Engine 51, Truck 81, Squad 3, Ambulance 61 and Battalion 25.

Borelli and Chili take their romance to the next level; Cruz receives a visit from one of his brother Leon's old gang members.

Mouch receives tickets from one of the members of the rock band Rush and Boden and his wife Donna welcome a new neighbor who turns out to be overly friendly.

Hermann is rushed to Chicago Med after being stabbed at Molly's by the young gangbanger he tried to rescue from that life.