Ethan and Clea discover what happened to Regan. They race to find the accountant before he's taken out. As authorities close in on Ethan, he and Clea work to uncover a greater conspiracy.

Harper finds out Mia's true identity and tries to leverage this to make her turn on Marty. Ethan must decide if he trusts Mia or Marty while the three pull a heist together. Marlon turns back to his old gang lifestyle.

Ethan goes into hiding after the bombing of the Federal building. The bookseller holds Clea captive. Theresa scrambles to tie up loose ends in her hunt for Ethan. Regan agrees to assist Ethan and Clea, but it's a step too far.

Grace is jailed after being arrested for murder; Mitch and Wilson discover they share common interests; Tom is among the witnesses questioned by Hernandez and Campbell; Alec meets with Jimmy's crew.

Ethan and Clea work together to discover who's behind the conspiracy. Ethan forces Theresa to reveal her hand. Clea follows a seemingly innocent bookseller. Ethan does Theresa's bidding to unexpected ends.

Ethan helps Clea with her case before double-crossing her. Patrick catches up with Sadie. Clea figures out the identity of the mystery man killed at the warehouse. Ethan, Mia and Marty join forces for one final deal.

Harper contains Patrick; Marlon is arrested for Talia's murder; Ethan makes a new deal with Marty, who learns that Marlon betrayed him; and Harper breaks the Hutchings' murder case wide open.

The truth behind Sam's death is revealed. Jimmy meets with the Chinese. Grace confronts Sam's killer. Campbell and Jimmy come to an agreement.

Ethan discovers that the Russian mob was hired to kill Mia; Patrick agrees to help Harper investigate Greg Barrett's murder; and Marlon tries to get his assets back.

Ethan deals with an unexpected gunman and questions whether Mia can be trusted. In other events, Marty tries to contain the damage after the audio of Talia's death is leaked.

Ethan and Ray fall out. Grace says sorry to Evie. Leni and Grace find out the original source of Ethan's money. Sarah and Grace work together to track Ethan and Ray.

Grace must face the verdict of the internal affairs review board. Jimmy believes one of his sons is dead. Grace tries to comfort Jimmy. Grace's fingerprints are discovered on a gun.

Ethan discovers Tilda's plan to kill him, but gets the upper hand, interrogates her, and learns the truth. Marty forces a captured Mia to use the flash drive. Harper deals with the aftermath of the task force being shot up.

Mitch warns Grace about confiding in Jimmy about her suspicions regarding Max. Max is aware of Grace's real identity and tells Alec. Grace and Mitch go to the parking lot where she was supposed to meet Michael Chen.

Tragedy strikes the Travis family. Tom tries keeping the family together. Grace convinces Jimmy he has a traitor in his organization. Mitch hesitates to help Grace. Jimmy discovers his money is missing. Max returns home. Jimmy and Grace make a deal.

Grace is on a special FBI taskforce investigating a prostitution ring. Her home life is complicated by her mother, Vivian, who shows up after a prolonged absence. Tom has something to tell Grace. Ethan and team negotiate their first contract.

Jimmy Laszlo learns Grace's true identity. Alec takes revenge against a rival gang. Jimmy strikes a deal with Grace to find the traitor in his organization.

Ethan tracks down Clea while getting dragged deeper into the world of Casey Oaks. Clea investigates Oaks' possible involvement in Maria's murder. Mia reconnects with an old accomplice. Patrick struggles to come to terms with Harper's death.

A firebombing drops the Laszlos between a vengeful Chinese gang and justice-seeking police. Grace finds a link between Jimmy's organization and the shooting outside Sam's school.

Grace is still missing. Ethan heads to Chicago to investigate notorious attorney Marty Stein. DEA Agent Harper Deakins' investigation into one of Chicago's deadliest gangs takes a turn when a routine stakeout goes wrong

Grace works to escape. Ethan reconnects with his father. Escalating gang warfare spills into the suburbs. Ethan investigates Marty's leak at a party, where he meets Marlon Dinard, who is not what he seems.

Grace has a police insider trace the money found in Charlie's safe; Alec learns that Max will be taking over Charlie's business; Tom seeks comfort with Shelley; a masked gunman ambushes Grace.

Ethan searches for a missing woman; Harper tries to turn Marlon; and Marty plots Marlon's prison release.

Grace discovers Ethan hasn't been truthful about the night Cheat died. Leni reaches out to a Pentagon contact and discovers how Ethan and his team met. Detective Lee tails Ethan. Ethan and the team feel they're in danger. Billy and Evie grow closer.

Grace thinks about going undercover whilst Elliot tells Leni aoff about her contact in the Pentagon. Spud and Ray find an unlikely new ally.

Sam's death is linked to Jimmy's crew; Jimmy delivers a scolding to Alec; Capt. Campbell seeks dirt on Jimmy; Max receives word of the missing money.

Grace confronts Elliot and Leni about her concerns for finding Sarah. Evidence is uncovered. Detective Lee becomes a liason. Elliot reveals to Leni the true nature of their investigation. Ethan, Ray and Spud find out about Cheat and take action.

Grace heads to Chicago to work with Ethan. Marlon appears on Harper's DEA radar. Harper's CI, Lobo, is made. Ethan finds Marty's leak.