Olinksy becomes a person of interest as Woods dives deeper into the murder of Kevin Bingham. 

IAD brings Olinsky in for "questioning," where it's revealed that his hair was found on Bingham's body. 

Woods tries to convince him to give his buddy Voight out by convincing him that "everyone has a price."

But Olinsky isn't one to be swayed into talking, even after Woods reveals that they have a witness that place Olinsky and a 20-something-year-old at the scene of the crime. 

Voight realizes that not only would Olinsky pay for his crime, Lindsay would too. 

And she's his weakness. 

Olinsky asks Voight to borrow some money from his "rainy-day" fund to hire a lawyer, but the money has already been invested in his grandson's trust as Voight thought he was going to get arrested any day. 

Voight tells him they'll figure it out and they almost do when they bust into a stash house with more than two-hundred thousand in a bag under the bed. 

It seems like Olinsky considers pocketing some but some members of Intelligence walk in and become witnesses. 

The stash house is part of their case-of-the-week, which finds a prominent alderman shot and killed in a city alleyway. 

At first, it seems like just a normal robbery but soon they realize that Alderman Burton recently passed an ordinance allowing blighted areas to skip out on paying property tax. 

Thus, he had a lot of enemies. Some of those enemies disclosed their hatred for Alderman Burton and his son, Arthur. 

Eventually, Voight realizes the two were trying to put up a property in the middle of The Heroin Highway. 

If condos were to go up, they would screw up the business model. 

By that point, it's already too late because Arthur is executed just like his father -- one shot to the head. 

Voight tracks down Lamar, the leader of The Westside Disciples but he's "done" talking, which basically tells Voight everything he needs to know. 

They track down the car, a blue Chrysler sedan, and pinch Keon. They find the AR-15 in the trunk but Ruzek quickly points out that the shoes in the back were a size 11 which is way too big for his stature. 

They follow the breadcrumbs to a nurse at what seems to be Med, who confesses that Keon is a patient with sickle cell anemia.

He doesn't have a "bad bone" in his body but his cousin Lamar definitely does. 

They release Keon, who doesn't seem likely to rat out his cousin and follow him to a convenience store. He buys a burner phone and makes a call to warn Lamar that the cops are onto him.

When they arrive at Lamar's house, he tries to make a break for it but is knocked to the ground in an epic takedown by Ruzek. 

They bring both Lamar and Keon in but neither of them is willing to talk. 

In fact, in an attempt to cover for his cousin, Keon admits to killing both the father and son. 

Finally, Olinsky finds his weakness point -- his disease. 

Before they charge him, they inform him that there won't be any doctor visits in prison so all the medication he needs for the chronic pain will be unattainable. 

Knowing that he won't be able to manage it, Keon confesses. 

The case mimics what Olinsky and Voight are going through with the Bingham investigation. Will one of them crack?