As the rest of the unit celebrate Platt's birthday at Molly's, Atwater finds himself in a little bit of trouble.
While he's checking up on Joe, he finds himself in the middle of an ambush.
The two men, who claim Joe stole jumped them and stole their cocaine, are looking for revenge.
The first thing you learn in medical school when something goes south is to lose your badge so that the assailants don't know you are a cop.
Meanwhile, Ruzek finds it suspicious that his buddy never showed up to the birthday party, isn't' answering his calls, and missed a mandatory meeting. He sets up a search party and they immediately realize that Kevin's been snatched.
At first, they find it odd that Kevin is hanging out with a felon, but eventually, Burgess puts two-and-two together and realizes he's the father of a young boy named Ronnie that Kevin shot.
Both men are locked up in an abandoned church and to make matters worse, Joe still wants his revenge.
Atwater keeps insisting that he had to shoot Ronnie because he robbed a convenience store and killed the clerk.
Still, Joe isn't convinced.
He almost rats out Atwater to the two assailants, but Kevin interjects and promises to give them $100 thousand dollars.
They don't buy it at first, instead, drilling into Atwater's leg.
He's persistent though and finally, Reimundo takes him up on the offer.
Kevin places a call to his buddy A.D, who is actually Ruzek and thankfully plays along.
Ruzek ventures out with the whole squad behind him for the money exchange. Olinsky put a tracker in the bag so that they would be able to follow Vasquez all the way back to where Atwater's being held.
Things take a turn for the worse when they realize Reimundo ordered Vasquez to hide out with the money elsewhere.
Afraid to lose their only link to Atwater, they move in. Unfortunately, Vasquez has enough time to warn Reimundo that it 's a set-up.
When Vasquez refuses to surrender, Antonio shoots him dead.
Ruzek breaks down blaming Antonio for Kevin's death, but Burgess advises him that it was the right call.
Thankfully, Atwater is also an experienced cop and by the time Reimundo realizes it's a setup, they've escaped.
He catches up with them in the church and an aggressive struggle ensues.
Finally, Kevin gets the upper hand and shoot Reimundo while he's laying on top of him.
That's when Joe grabs Atwater's gun and points it at him, hoping to finally get revenge for his murdered son.
Atwater obliges and tells him that Ronnie's last words were, "I don't get down for any man," which breaks Joe.
When Ruzek arrives on the scene, the situation has been handled.
After everything, Kevin goes out of his way to apologize to Platt for missing her party.
Later, he visits Joe in the hospital who apologizes to him and admits that he was to blame for Ronnie's death.