The team knows they need to track down this T.K. person before Oliver, who assures his wife that he'll get their daughter back. He's a man of his word. Oliver finds Izzy at the dealer's apartment. She's been roughed up. This sends Oliver into a fury. He drags T.K. into another room pointing his gun at the lowlife's head. Oliver isn't a cop right now. He's a father who wants a certain kind of justice brought to the man who hurt his child.
Sam and Andy arrive at the scene. Oliver asks if they'll back him up should he shoot T.K. in the head. The answer is yes. Whatever he needs. Izzy enters the room. She sobs for her dad to not do this. Her plea works. Oliver holsters his weapon. He lets T.K. know that Izzy just saved his live. It's the end of an emotional scene where one of our favorite cops almost went down a dark road in which there was no turning back.
Oliver brings Izzy home. He breaks down when his daughter says she misses him. Zoe comes out to the car. She can see that her husband is in a fragile state. She asks Oliver if he'd like to come into the house. He would. The three of them head inside. At least for the moment, the Shaw family is together again.