When a star witness in a double murder case drops out, Erin is tasked with bringing a protected mob informant back to New York for a case and keeping him safe, with help from Danny and Maria. Also, Frank enters into tense negotiations with Mayor Poole about police officer benefits. Dan Hedaya guest stars.
Dr. Choi (Brian Tee) struggles to help a woman cope with anorexia. After a two-week suspension, Dr. Reese (Rachel DiPillo) is immediately put to the test upon her return by Dr. Charles (Oliver Pratt). Dr. Rhodes (Colin Donnell) takes a stand when one of his patients is forcibly transferred. Meanwhile, Dr. Halstead (Nick Gehlfuss) is on a mission to get Dr. Manning's (Torrey DeVitto) son to like him.
Gigi’s success on the NYC scene leads to The Heathens finding out they are somehow still big in Belgium.
When Jack dates a millennial to avoid commitment, he needs Clark, Emma and Mason's help to keep up with his new girlfriend, Kaylie (Caitlin McGee), and her exhausting lifestyle.
