Liz E. Morgan

The pursuit of a missing teenager leaves Mills and Brett stranded in unforgiving elements; members of the firehouse care for an abandoned newborn; Severide receives an intriguing proposal; Boden is at odds with his father.

A temporary chief fills in for Boden, who is forced to take some time off for personal reasons; Lt Severide deals with an unwelcome addition to the squad; Brett becomes close to a girl she previously rescued; Casey starts seeing a new woman.