Antonio (Jon Seda) and his sister Gabriela (guest star Monica Raymund) go to the office of Elliot Gish (guest star Robert Knepper), the man they believe started the fire that killed Shay. Intelligence along with patrol officers Burgess (Marina Squerciati) and Roman (Brian Geraghty) put pressure on Gish to try and make him confess. Lindsay (Sophia Bush) approaches Voight (Jason Beghe) about returning to Intelligence when she realizes that the task force isn’t what she thought it would be. At the same time Desk Sgt. Platt (Amy Morton) is acting strange and has everyone curious as to why she’s being overly cheery, friendly and nice.
When a gang from El Salvador infiltrates Chicago, Intelligence works with a visiting detective to put an end to the crew's brutal tactics. And Antonio (Jon Seda) finds himself getting close to the Salvadoran Detective, Marcella Gomez (guest star Sofia Lama), only to learn she has a hidden motive for being in Chicago. Meanwhile, Voight (Jason Beghe) learns that the body of his son's killer has been found.
After the discovery of a serious medical condition, Mayor Tom Kane must set things in motion for the upcoming gubernatorial primary while attempting to reconnect with his distant wife and estranged daughter.
As Zajac's campaign gains momentum, Kane has problems adjusting to his new medical reality. An embarrassing media storm catches Governor Cullen off guard while Miller stumbles upon a story that seeps much deeper than he imagined.
In the aftermath of the Steelgrave case, Vinnie tries to vindicate himself of his lingering feelings of betrayal and disloyalty by risking his life to save an old friend from the Brooklyn neighborhood who has a contract out on him.
