Ruzek and Voight respond to a gruesome murder scene in which a bunch of junkies randomly stumbled upon a dead body dumped in acid.
The woman, Isabel Pena, was identified as Gael's girlfriend. Gael is a top crime lord in Chicago that PD has had their eyes on for a while. The problem is that he's so good at staying clean that no one can even nail him.
Voight orders Atwater and Rojas to set up the buy while undercover when Rojas spots someone she knows at the club.
She tries to distract the man, Reyes, by making out with him while Atwater solidifies that deal.
She later tells Upton that Reyes is a lifelong friend and her on-again-off-again boyfriend who has no idea she's a cop.
When Atwater and Rojas' buy is shot down by Gael, they resort to a wire case, which means the bug all of his cars, listen in on every conversation, and watch TJ's every move to build the case.
Rojas sees TJ pop up on the surveillance cameras and erases the footage only to find out that this case is going to be under the microscope.
She confronts TJ who tells her he's clean, so she comes clean to Upton and vouches for TJ.
Upton says she'll handle it.
They need to put the pressure on the deal so they begin flooding the market with fake drug buys, which causes one of the buyers, Tyrell to request a re-up. Gael gives the okay and they arrange the meeting for the next day with Reyes.
Rojas is fuming when she hears her ex is involved after he swore he wasn't.
She confronts him at his shop that night, but Reyes tells her to stay in her lane.
He explains that he took the rap for her before and now he has to make a living somehow.
She urges him to get out of the game while protecting her secret.
Once she gets home, Voight appears at her door and questions if she broke the law and tipped Reyes off.
Rojas informs him that she didn't, but that doesn't quell Voight's anger.
He informs her that she chose to be a cop and she has to do the right thing here.
The next day at the buy, TJ doesn't show and Rojas and Upton arrest Reyes, who is shocked to see his girl as a cop.
He is fuming and tells Upton that he never even knew Rojas.
He tells them everything he knows about TJ in exchange for a lighter sentence. He also informs them he usually sees both Gael and TJ a day after a major reup.
They wire him up, but when they arrive on the scene and neither of the men show, they realize something is up.
All of their cameras and phones begin going dead. They drive over to TJ's car and find him dead.
Gael was onto them somehow.
The State's Attorney refuses to cut Reyes the deal. Rojas breaks the news to him and apologizes, but he's not interested in her excuses.
Upton then pulls Reyes aside privately and asks him to tell her everything about the traps he placed in Gael's cars.
The next scene shows Gael getting pulled over as Upton watches. They pull product and the trap from his trunk.
Voight pulls Upton into his office and demands to know why she planted the evidence.
Upton stands by her choice and assures him she believed it's what he would have done, which angers Voight.
"I don't want you to be like me," he angrily yells.
He then informs her that he volunteered for her to work with New York's FBI task force for a few weeks where they have lines that are "real clear."