Season 4 Episode 10
"The Beating Heart"
Herrmann fights for his life after being stabbed; Cruz hits the streets to find Freddie; Mouch proposes to Trudy.
We find Herrmann (David Eigenberg) where we last left him, lying in a pool of blood in the back room at Molly's. After being found by Dawson (Monica Raymund) and Otis (Yuri Sardarov), Herrmann is whisked off to Chicago Med. Controversy ensues when Dr. Rhodes (Colin Donnell) makes a medical decision concerning Herrmann's treatment - a judgment call that some feel may have hurt Herrmann's chances for survival.
Chicago P.D. and the Intelligence unit are brought in to assist in finding Freddie, Herrmann's attacker. A guilt-stricken Cruz (Joe Minoso) takes to the streets to find Freddie, a dangerous move that puts Cruz in harm's way when a member of Freddie's gang pulls a gun on him. Freddie is found, trapped on top of an apartment building, and Cruz makes a risky move to save his life. Once in custody, Freddie attempts to apologize, but Cruz reminds Freddie that he "let it happen."
Although Herrmann initially responds well to treatment, his condition takes a turn for the worse and a massive loss of blood leaves his fate up in the air.
Mouch (Christian Stolte) haphazardly proposes to Platt (Amy Morton), in part because Herrmann insisted Mouch not wait until Herrmann was out of the hospital. Although Platt initially doesn't respond to Mouch's proposal, by the episode's end they are engaged.
A suicide attempt sets an apartment building ablaze, with Casey (Jesse Spencer) and Dawson barely escaping an explosion. Chicago P.D. investigates the fire on the suspicion that foul play may be involved.
Chili (Dora Madison) continues her downward spiral, growing more and more distant to those around her. Brett (Kara Killmer) attempts to draw Chili out, enlisting Borrelli's (Steven R. McQueen) help in the process, but whatever's troubling Chili, she's not saying.