Antonio is on the phone with his ex-wife. She’s been slacking on the motherly duties of late and he’s had to pick up the slack. Voight comes in. They’ve got a body. Turns out its a key witness in the case that Peter Stone (Philip Winchester) is trying in court. The defendant is a serial rapist and killer and a link to the death will lock him up for sure.
The unit starts brainstorming on the murder and trying to find a connection to the defendant Oliver Tuxhorn. The victim was also in protective custody so they want to talk to his security detail. When one of the guards gets in, he explains that the victim got a call or a text that rattled him while they were at the hotel the night before. He went to the gym but must’ve slipped out the backdoor and that’s the last they saw him. Voight tells him that he and his team will be investigated.
The victim’s widow is at the district. Lindsay talks to her about her husband and what they went through before the trial started. They were being followed until he was put in protective custody. She knows it was Tuxhorn or his rich father that set up the hit on her husband. They just need to prove it.
Lindsay goes to court and listens to the statements about the impact of the murder on the case. Tuxhorn is let free and she talks to him outside before his lawyer hurries him off.
At the district, Voight is going over the board when Lindsay walks in. She says that she could see in Tuxhorn’s eyes that he was guilty. That’s good enough for Voight. He sends Ruzek and Atwater to talk to the victim’s best friend. He’s got a gun that matches the one used in the murder.
Antonio updates Winchester on the case and gets a job offer in the process. He turns it down but Winchester tells him to think about it.
Halstead and Voight are in interrogation with the best friend and they keep pushing him, especially when he comes back with no alibi but he’s adamant that he didn’t do it. He even starts crying.
Burgess and Sorenson are on patrol when they see a car swerving. The pull the driver over and he is wearing a skirt and a chastity belt. There is also an outstanding warrant for him in Milwaukee so they have to take him back to the district.
Lindsay does some digging and finds footage of the best friend on the bus at the time of the murder. He’s being set up.
Antonio took the digging a few steps further and found out that the call from immigration to the best friend was faked and that he lost his job because of an anonymous tip.
Halstead and Lindsay have the opportunity to talk to Tuxhorn but he is no use to them. He’s just smarmy and annoys them really.
Sorenson is recording the footage from his uniform cam on his phone and Burgess is not amused.
A money specialist confirms that there is nothing sketchy about the victim’s finances and Voight gives him 10 hours to figure out how Tuxhorn paid the killers. Antonio asks Voight why he’s pushing him out of the unit and Voight tells him it’s his time to run his own crew.
Olinsky goes to visit an ex-cop that works as a PI for Tuxhorn. He admits to working for the family and says that the brother Leo took particular interest in the eyewitness. He wanted to get close to him.
The unit goes after him and nabs him for possession. Lindsay heads to a club to let Tuxhorn know they are closing in on him.
Voight and Atwater head into interrogation with Leo Tuxhorn (Chris Froseth). He tells them he’s a lot of things to a lot of people but he’s not a killer. He tells them he was at a party and has an alibi.
Sorenson posted the video on Facebook and Platt is disgusted with him. Burgess tries to defend him and they are both put on foot patrol.
The money man has traced a connection between the Tuxhorns and a shell account overseas but it’s not enough. They have a somewhat loose connection based on a Facebook post so they call in the sister and after a little questioning she lays out the whole plan. It involved the PI and Olinsky goes to arrest him.
Tuxhorn gets locked back up and they state’s attorney is going to go after his sister now too.
Burgess is moping about her partner and Platt tells her that she’s doing all she can. Burgess knows. She turns around to leave and Antonio starts to talk to her but then decides not to.
Antonio heads to 51 and talks to his sister about the move to the state’s attorney’s office. She helps him see that it would be better for him on all counts. He heads to Molly’s and meets with Stone to accept the job.
Halstead and Lindsay are at a diner. He’s about to meet her mother, Bunny (Markie Post), formally. She comes in and asks Halstead to give them a minute. Lindsay says no and they argue but before they can get any further an officer down alert comes over the radio. They respond and find the officer was shot. Soon the complex is swarming with cops. Olinsky figures out where the shot cam from. It was an execution.
The down officer’s partner, parents and several others are waiting at Med. Will Halstead comes out. The officer didn’t make it.
The unit is trying to piece together what happened but there are far too many open angles so Voight tells them to narrow it down. Lindsay asks Antonio if it’s true he’s leaving. He confirms that it is.
Crowley wants an update from Voight. There is a lot riding on this case because of the climate of the city. He knows it but before they can agree on anything Ruzek comes in with a lead.
The team chases down someone that fits the bill of the shooter and brings him in. He says he didn’t do it because he would’ve shot an older cop.
They get another lead and go to chase is down but when they approach something feels off. Halstead tells them to wait and another officer gets shot in the head. They try and clear the officer out and give chase but they are too late. The shooter gets away and the officer dies.
Halstead gets angry. It was military precision. They were sitting ducks. They start to narrow down the board but its still a lot. Lindsay gets a hit on a possible military trained suspect.
Crowley holds a press conference while Platt tells the district to keep their heads up and hace each other’s backs. They stake out the suspect but get made and have to chase him. When they get him out of his car, it’s full of guns. They take him back to the district and toss him in the cage.
He spews about cops being the real enemy and that he hopes they all die but he has an alibi.
Platt tries to send Sorenson and Burgess out again but Sorenson can’t handle it. He hands in his badge.
The unit has another suspect since the last one’s alibi checked out. A former academy cadet that was kicked out for erratic behavior. He’s the son of a cop killed in the line of duty. They head to his mom’s house to find him but he’s living on his own with a roommate and the demand the address from her.
At the house they find the roommate dead and elaborate plans for the killings. The guy is in the wind though. Dr. Charles come in to talk to the team about the suspect’s mental state. They also talk to his mother again. She asks them not to kill her son.
Voight and Olinsky talk about the night the suspect’s father was killed before they move in on where they believe he’s holed up. Voight gets the suspect Carl Dougherty (Dave Thomas Brown) on the phone and talks to him. Carl wants a hostage negotiator because he has people inside. Voight keeps him talking while Lindsay sneaks up to the house to look inside. It’s rigged up to explode and there are hostages including a little girl.
Carl wants to bring in support so that he can blow up the house and kill as many cops in the process as he can. Voight keeps trying to talk to him but the kid isn’t listening. He hangs up on Voight and the call is made to shoot Carl.
A service is held for the fallen and Olinsky is the one to tell Carl’s mother.
Halstead thanks Antonio for all he’s done for him, bringing him into the unit and all, and Antonio tells him that he’s proud of the cop he’s become. They head to Molly’s.
Voight talks to Burgess and offers her the empty spot. She accepts it.
Antonio comes in and thanks everyone. He tells them it’s been an honor working with them. Lindsay gets a call from Bunny and leaves the party. Apparently her father is in town and wants to see her.
I’m going to miss Antonio. Even though he’ll still turn up and I’m going to watch Justice it will be a different show without him but his screen time has been cut a ton this season so it makes sense. I’m pretty curious as to what is going to happen with Lindsay’s father. Since Voight and Bunny don’t get along I assume that goes for her father as well so that should be interesting.
Chicago PD returns Jan. 4.