The episode starts with Voight getting ready to go on record with the truth about Kevin Bingham's murder, much to Denny Woods' delight. 

He ignores his phone the first time, but as it keeps ringing, he finally picks it up. 

Without saying a word, he bolts out of there and to what we presume is Gaffney where his best friend Al Olinsky is being rushed into emergency surgery after being stabbed multiple times outside of his prison cell. 

We see Voight pace up and down the halls before finally asking a doctor about the status. 

"I'm sorry, he didn't make it," the doctor says nonchalantly. 

When Voight breaks the news to his team, he encourages them to honor Al's legacy first by finding the "son of a bitch who did this to him." There will be time for mourning later. 

It's all-hands-on-deck as everyone wants to avenge Olinsky. First, they realize the corrections officer that was supposed to be "helping" Al was actually paid off to turn a blind eye. 

He revealed that it was actually a paid hit and eventually, the name of the prisoner responsible. 

As Antonio and Ruzek kept guard, Voight roughed up the prisoner to get the name of whoever hired him. 

This led them to the cartel member who had a grudge against Al for killing his brother when he was loaned out to the DEA task force. 

After they track him down, Voight tries to evade Antonio who, on multiple occasions, expressed his disgust at how Voight handles certain situations. 

Voight cornered the man who ordered the hit but he cowered and offered Voight money in exchange for his freedom. 

Showing no mercy, Voight took the shot with the guy's hands up in the air just as Antonio arrived. 

Voight was able to lie to him which was fun, but he failed to realize there were actually witnesses who saw what happened. 

Antonio is conflicted about whether or not he should sell out Voight or lie to the board and say he took a legit shot. 

Meanwhile, Woods felt the case slipping away so he decided to put the pressure on and find more than just circumstantial evidence. 

When he heard Osha say a new witness in the case may have come through, he met with her and realized that she was going to be his saving grace. 

The girl refused to give her account of what happened unless she was paid a hefty sum of money to which Woods agreed. 

After he gave her the first half of the payment, he told her to "make adjustments" to her testimony and she agreed. 

That night, Voight stopped by Woods' house to "chat." He gave him a pretty logical pep-talk about how the really dirty cops, much like himself, do what the others don't. They kill terrible people which is necessary. 

Then, he reveals that Woods walked right into his set-up. Blue lights flash outside the window as Woods is arrested for bribing a witness and probably many other things. 

After everything is said and done, Voight goes on the roof to drink and mourn Al. 

He's heartbroken and blames himself for Al's death.

"I'm sorry," he tells him and then contemplates jumping from the building.