At Chicago Medical, Intelligence breathes an uneasy sigh to hear that Antonio remains alive (Belden, however, was not so lucky). Voight takes Pulpo's actions personally - he demands that the team find the drug lord and then deliver him to Olinsky and Voight, no questions asked. This last part doesn't sit well with Halstead and he voices his opinion on Voight's cowboy justice. But before things escalate, another body drops - Pulpo's most trusted man. So who's he got left? After a few dead ends, they finally get a hit on a credit card and locate Pulpo's secret family... but not him. They interrogate his mistress only to discover that Pulpo ditched his family as a diversion.
With the team distracted by the manhunt, Jin once again meets with Stillwell, sharing a thumb drive of stolen files. Stillwell shakes his head - not good enough. He wants wire taps ASAP or Jin's father will get a visit from the FBI. Jin reels from the incident, but maintains his composure later when Voight asks for his intel on Sumner. Her call sheet shows a handful of calls to Stillwell, which serves as more than enough evidenced to convince Voight of her guilt - and he transfers her to Narcotics. No sooner does Sumner pack her things than Voight announces Sumner's replacement... Atwater. Burgess asks Voight why he chose Atwater over her and Voight's response deflates her - he doesn't tolerate in-house romance.
Back with the Pulpo case, Intelligence returns to the drawing board and finds another angle - Russian nightclub owners apparently attempted to post Pulpo's bond. Voight and the team raid the nightclub and confiscate a laptop, then enlist Otis from Firehouse 51 to help translate. Turns out the Russians owed Pulpo a favor and agreed to smuggle him out of the country inside a shipping container. The club owner makes a deal with Voight and offers up Pulpo's location - and they find the fresh-shaven drug lord without incident. As promised, Voight dismisses everyone except Olinsky and they drag Pulpo to an undisclosed warehouse.
Halstead, enraged by Voight's decision, visits Antonio to relay the news about Pulpo... and how it's unlikely to air on the evening news. Sharing Halstead's conviction for justice, Antonio tells him where he thinks Voight and Olinsky would take Pulpo: the docks. Sure enough, that's where Halstead finds the three of them, moments before sinking Pulpo into Lake Michigan wearing a "Chicago necklace" - chains around his neck linked to cement blocks. Voight refuses to give in - until Olinsky sides with Halstead. Pulpo will receive his day in court.
The intense aftermath sends Olinsky back to the arms of his wife - he wants to restart their marriage - and leads Voight to bar, where Halstead joins him. Voight buys his round and surprises Halstead with encouragement - he respects the detective's conviction, even though they don't always see eye to eye.
In similar fashion, Lindsay's friend Charlie from her pre-P.D. life appears once again, and she arranges a dinner with him and mutual interests - an old friend Annie and her 12-year-old son Travis. Charlie scoffs at the prospect until Lindsay informs him that Travis is his son, too. The dinner stays civil (and awkward), but takes a curious turn when Charlie, in private, demands Lindsay answer the following question: do you owe me? She eventually says yes - which produces a smile on Charlie's face. Whatever he's planning, it can't be good...