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.

Harper is hit hard by Lobo's death; Ethan tells Marty the real reason he's in Chicago; Talia causes problems for Marlon; Grace and Ethan spy on Marty and the General; and Grace follows a dangerous lead.

Talia is arrested, which causes a headache for Marty; Harper uncovers another clue in Hutchings' death; and Ethan searches for Grace and tries to rescue his father before it's too late.

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 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.

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 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 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

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.

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.

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 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.

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.

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.

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 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.

Grace learns about the missing money from Jimmy before investigating the abandoned shooting range; Grace sends Tom and Evie packing; Grace gets into Santa Rita with Mitch's help.

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.

Ethan scrambles to raise money to pay off Mia. Mia targets Ray's kids and convinces Sadie to help. Clea searches for the trafficked girls. Patrick surveils Ethan in the hopes of catching Mia.

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

Grace is shocked when someone from her past, re-emerges. Leni's contact provides her with more information. Grace finds out about Billy's scrap. The force decide to plant a bug in order to spy on Ethan's team.

Spud looks for help from Ethan and Ray, and comes up with a plan to leave town. Grace shares her findings about Ethan with Leni and Elliot.

Ethan reveals to Grace they borrowed money from the wrong men. Ray realizes something is wrong with Spud. Ethan, suspicious, digs into Grace's background. Grace tries to help Billy but it backfires. Spud and Ray have a heart-to-heart talk.

Ethan and Ray are forced to figure out what to do about Spud. Leni and Grace speculate about the money Ethan has given away. Ethan tracks Grace. Billy tries to win Evie back. Evie confronts Grace. Grace finds a new clue in the search for Sarah.