The fall finale kicks off with Halstead coaching little Bobby how to play baseball.
Upton confronts him about getting involved with a previous suspect's family, but he informs her that he knows what he's doing.
When he leaves the scene of a crime and doesn't show up at work the next day, Upton begins to worry.
Platt traces his vehicle to a sketchy neighborhood and they find blood inside Angela's house.
Upton comes clean to Voight that Halstead has been supporting Angela and Bobby, Marcus West's family, out of guilt.
Voight agrees that they keep this case off-the-books and they begin their investigation.
Pretty quickly, they realize that Angela was responsible for stealing drugs from the Silva family.
Voight reaches out to Darius Walker and asks him to arrange a meeting with Pedro Silva. Walker is hesitant but doesn't have much of a choice.
Atwater pretends to be one of "Jim's" (Halstead's undercover name) men and promises to return Silva's drugs to him in exchange for Jim and Angela, who he says got played by Carlos, a man they found overdosed.
Pedro agrees, but when they meet up later, his men attempt to kill Atwater and take the drugs back.
Intelligence captures Pedro and takes him to the hole.
Since Pedro refuses to talk, Upton suggests leveraging the only thing he cares about, his high school son, Emilio.
When Pedro sees that they've taken his son, he gives up the location of Angela and Jay's holding place.
Meanwhile, Jay tries to break free and keep Angela calm.
She keeps blaming herself for how Marcus' life turned out, and finally, Halstead tells her Marcus wasn't the killer.
He informs her that he was the cop who put Marcus into county and got him killed, and assures her that Marcus never killed those boys.
Angela is disgusted by Halstead and threatens to tell the men holding them hostage that he's a cop.
Halstead advises against it because if she does, they'll kill them both.
Eventually, Halstead is able to get free and knocks out the younger and nice brother.
He then makes his way upstairs where he stabs the old brother who's calling all the shots.
At the same time, Upton arrives on the scene.
The two exchange a meaningful glance as Halstead goes back downstairs to get Angela, who has bled out a lot.
With her last ounce of strength, Angela grabs the gun and shoots Halstead.