Gene Weygandt

A suicide note is delivered to a surprised Dawson (Monica Raymund) and Lt. Severide (Taylor Kinney) digs deeper into Bloom's (guest star W. Earl Brown) dark past. Elsewhere, Chief Boden (Eamonn Walker) learns shocking news, and with the help of Shay (Lauren German), Lt. Casey (Jesse Spencer) goes on the search for a life-changing item.

Lt. Severide (Taylor Kinney) hits the top of the list as Det. Lindsay (guest star Sophia Bush) starts calling in suspects with the clearest motives to make the guy who kidnapped Katie disappear. Meanwhile, Jones (guest star Daisy Betts) is still having trouble fitting in as word of her disruptions reach the fire department's headquarters. Elsewhere, Herrmann (David Eigenberg) celebrates his twentieth anniversary with his wife, but no one supports his idea on the gift he intends to give.

Severide (Taylor Kinney) feels sidelined as he leaves Detective Lindsay (guest star Sophia Bush) and the Intelligence Unit to do their job and locate his sister Katie (guest star Brittany Curran). Shay (Lauren German) gets an unusual tip from Chicago Blackhawk players Brent Seabrook and Duncan Keith, who makes friends with Clarke (guest star Jeff Hephner) and stop by Molly's. Meanwhile, Casey (Jesse Spencer) learns more about his head injuries after another close call and Dawson (Monica Raymund) pushes hard to pass the physical test at the Academy.

When the team responds to a semi-truck leaking hydrochloric acid in a busy intersection, Casey (Jesse Spencer) and Dawson (Monica Raymund) find their relationship being put to the test. Meanwhile, Severide (Taylor Kinney) learns more about Brittany’s (guest star Serinda Swan) past and Mouch (Christian Stolte) has some difficulties in his dating life.

Lt. Severide (Taylor Kinney) sticks his neck out for Dave Bloom (guest star W. Earl Brown), a fellow firefighter from Denver who is troubled by addiction. Elsewhere, Dawson (Monica Raymund) and Shay (Lauren German) leave town for a "girl's weekend" at a cabin in the woods. Meanwhile Jones (guest star Daisy Betts) struggles with the knowledge that her father is pressuring Chief Boden (Eamonn Walker) about her career path and Mouch's (Christian Stolte) internet dating profile gets an upgrade with the help of Mills (Charlie Barnett) and the guys.