As the Sheldon Jin investigation moves forward, Internal Affairs keeps a close eye on Voight; Voight's vehicle is T-boned while following an armored car carrying Ruzek; Burgess meets her new partner; Lindsay visits her mom.
Several murder victims are found with a dollar bill pinned to their chests; Voight makes a discovery about a friend; a series of home invasions.
When a bartender takes a bullet intended for Halstead, the bounty on him becomes more real; following a tense interaction, Platt and Nadia reach an understanding.
The team races against the clock when two teenage girls disappear; Voight seeks honest answers from the father of one of the girls.
Voight is attacked and abducted while trying to help Olive; Roman and Burgess search for a girl who has taken off with a police badge.
Ruzek and Atwater go under cover as prison inmates in order to find the man they believe killed a 10-year-old girl; Burgess and Roman give a tour of the district to some boys they believe are part of the Police Explorers program.
Detectives from New York's SVU come to Chicago to help take down a pedophilia ring; Platt shows her respect for the police.
When Asher is killed while Antonio is on his security duty, Voight and Olinsky make sure he is covered; Halstead and Lindsay go under cover; Kot wants an answer from Lindsay.
Following a big heroin bust, Olinsky learns that the suspects are holding his wife hostage; Burgess and Roman get an assignment that pairs them with a K-9 officer: Roman's former partner (Spencer Grammer).
The intelligence team works to find those responsible for Burgess' wounds; a search of the house provides valuable information.
Lindsay calls on Voight and his unit for help with her first case on the federal task force; Burgess is relegated to desk duty.
Ruzek's father (Jack Coleman) is first on the scene of a double murder; Lindsay prepares for an undercover investigation in Bolivia; Roman and Burgess try to move forward.
Antonio and his sister talk to Elliot Gish about the person they think is responsible for the fire that killed Shay; Lindsay has second thoughts about the task force; Platt's new, sunny demeanor results in curiosity.
Bunny comes to Lindsay with a concern that leads the team to a case that robbery-homicide has been investigating; Voight is suspicious of Bunny's motives.
Burgess and Roman become trapped after Burgess pursues suspicious activity at a convenience store without calling in for backup; the intelligence team receives taser certification.
When an undercover narcotics officer goes missing, Antonio is asked to help find him; Burgess and Roman ask Mouch (Christian Stolte) for help with a squatter situation.
The members of intelligence go under cover at a World Trade conference to assess political threats; Halstead's brother immediately stirs up trouble when he shows up in town.
An investigation into a drug robbery gone wrong reveals Voight has ties to a teen linked to a double murder; Desk Sgt. Platt cares for a young girl.
A case involving one of Chicago's most wanted fugitives hits close to home with Olinsky; an altercation with another officer lands Sean Roman in hot water; Platt helps Nadia prepare for her polygraph test.
After arriving in Chicago to assist Voight and the team with a rape/murder case that has distinct similarities to a decade-old case from New York, Sgt. Benson asks Fin and Amaro to help; the prime suspect asks for a meeting with Lindsay.
Still struggling with a loss, the team must put feelings aside when a cafe is bombed; Atwater winds up in hot water after making a mistake.
A mass shooting takes place in an athletic club; Atwater deals with his new assignment; Halstead and Platt try to check up on Lindsay.