Voight's son may be involved with the Fitori murder case, intensifying tension between Antonio and Voight; Ruzek helps Burgess get retribution.

Halstead's badge is revoked when Lonnie Rodiger is found dead; Severide and Clarke find Dr. Elliot's torso; Sumner tries to prove herself; Lindsay shares a moment with Severide.

Commander Perry notifies the Intelligence unit that Pulpo has been released to help track down a dangerous cartel leader. This doesn’t sit well with our team as he kidnapped one of their own and no love is lost between sides. Meanwhile, Ruzek gets some difficult news as a blast from Lindsay’s past comes back, giving us a glimpse at where she came from. Voight reminds her that she’s come too far to screw it up. At the same time we learn something about Jin that is bound to be a problem.

Atwater is settling into his new gig on intelligence as Antonio is relegated to desk duty while recovering. Lindsay finally realizes she has no way out and confides in Voight for help. Meanwhile Jin is confronted about his secret meetings with Stillwell.

As the Sheldon Jin murder investigation moves forward, Voight is under close watch by Internal Affairs but he’s still in complete command of the intelligence unit. A routine undercover job becomes anything but when Voight’s SUV is T-boned while trailing an armored car carrying Ruzek. Burgess meets her new partner, Sean Roman and tension is high from the start, and she soon realizes there’s more to his story. After a long day, Lindsay pays a visit to someone she hasn’t seen in a very long time.

While trying to help out, Olive Voight is attacked and taken. Ruzek and Atwater prove they belong on the team when they demonstrate smarts and savvy tracking down a lead that will hopefully bring them to Voight. Burgess and Roman try to track down a girl who runs off with a police badge.

The intelligence unit is joined by detectives from New York’s SVU to help solve the pedophile ring case. Ruzek, Amaro, Halstead and Antonio continue to hunt for the link to foster care and child trafficking. Burgess and Roman try to find the shooter from the hospital after using surveillance footage to identify him. Platt shows her deep respect for police and the dangerous work they do by honoring their fallen brother.

The crossover starts on Chicago Fire S03E07 Nobody Touches Anything (I) and Law & Order: Special Victims Unit S16E07 Chicago Crossover (II).

A friend of Nadia’s leads the intelligence unit to a huge heroin bust. Unfortunately this bust results in Olinsky arriving home to find the suspects are holding his wife. Voight and the team think they’ve found a common thread with the suspects but it’s not who they think. Meanwhile Burgess and Roman are given an assignment where they get paired with a K-9 officer, Jenn Cassidy who is Roman’s former partner and girlfriend.

Lindsay has her first case with the task force and realizes she needs to call on Voight and the Intelligence unit to assist. Meanwhile Burgess is back on the job, but relegated to desk duty which allows Desk Sgt. Platt the opportunity to partner up with Roman.

Burgess begins to regret her recent decision to stay on the beat. While at a convenience store she sees some suspicious activity and pursues it without calling in for backup. It's a slow day in Intelligence as they spend their time receiving taser certification.

Antonio heads undercover with a dangerous robbery crew after a narcotics officer goes missing.

When Voight's card ends up in the hands of a murder suspect, he aims to protect the man at any cost.

A mass shooting at an athletic club is investigated; and Atwater, who's dealing with his new assignment, helps locate the suspected shooters. Platt and Halstead, meanwhile, check in with Lindsay to see how she's managing.

Voight arranges for his former cellmate, Eddie Little, to be a CI in an effort to bring down a major cocaine supplier. Burgess makes a major move regarding her relationship with Ruzek. Roman develops a plan to help fund Platt and Mouch's wedding.