Hailey speaks to Atwater as they're the only ones in the bullpen. He checks in on her when she talks about how she went on another run.She updates him on how Voight is still desperate for a lead on the case.

When Hailey goes to get a snack and comes back, she sees a young girl. The girl talks to her and Trudy. She hands them a paper that gives her name and that she escaped.

They realize that her mother was a girl who went missing many years ago, it was a cold case. So they decide to take the case.

It was related to Petrovic. Hailey calls Petrovic to update her, but she realizes that she's drunk. Petrovic says that she's on her way, and Hailey is worried that she'll drive drunk, so she sends Atwater to Med with Hope, the young girl, and she tracks down Petrovic.

She finds Petrovic in her car and she crashed intno a wall. She's inebriated, and her head is bleeding. Hailey has to figure out whether or not to call it in.

Hailey gets Petrovic back in the passenger side of the car, drives the car into the garage and covers up the incident as best as she can while getting Petrovic inside.

She tosses Petrovic in the bath and turns cold water on her until she sobers up.

Hailey tells Petrovic that she's taking her to Med and she can work the case with her but takes her to rehab to detox and threatens to report her. Petrovic tries to plead her case for why she needs to work this with her.

Hailey interviews Hope and learns that she ran away while at the mall with the captor and her mother never gets to leave.

They get footage of the car at the mall and ID it and go to the house that it's registered to, break things down, and search the house. There are suspicious signs, the locked up windows and doors, and Hailey searches under the bed to find the punishment box Hope mentioned that "the monster'" would put her mother in, but it's empty and Ruthie isn't there either.

Ruthie was being held five minutes away from her home, and now they have to figure out where "The Monster" hast taken her.

Hailey goes to see Petrovic to talk to her and figure out what all she knows about the case and how she can help. Petrovic says she can help if she has some something to drink because she needs it to do her job. Hailey denies her. Jo lashes out at her and tells her that she has a problem herself and needs help.

The person who runs the rehab facility checks in on Hailey as she leaves after grabbing Petrovic's keys. She asks about Hailey's father and brothers. She hasn't seen her father in a decade and her brothers have left town as soon as they could.

The woman reminds Hailey that she's worth fighting for.

Hailey goes to Petrovic's house to pull the files she has related to the case and goes through all the previous suspects and notes she wrote about the couch.

Hailey goes in to see Hope and Ruthie's mother left the room. Hope tells Hailey that the mother is "pretending." The woman comes back and Hailey has her going through the pictures of suspects. Ruthie's mother lies about recognizing a guy but Hope visibly recoils at the picture of one of the men.

Ruthie's mother is obsessed with Hope and feels she's just like her little Ruthie.

They look into Sonia, but don't find anything.The others ask Hailey about Jo, but she doesn't give any answers. Petrovic shows up while they're on the case and she tells them that Sonia redecorated her living room and bought a new couch. It was suspicious.

She had a drink and came to help.She says Hailey can report her after she helps them solve the case.

They connect Sonia to a guy who was a tech criminal. They find all his seized laptops in the evidence room since he was previously imprisoned. and they realize that Sonia sold her daughter to a sex trafficker.

They go to the hospital to arrest Sonia. She puts up a fight so Hailey and Torres have to take her down, while Atwater heads out with Hope.

They take Sonia in and book her and do things off. But they get a lead on where the perp is.

They breakdown the house and end up shooting the perp when he tries to shoot them. They search the property but don't find Ruthie. Hailey remembers that he likes to keep her in closed spaces. she finds Ruthie alive in the AC unit and takes her to the hospital, reuniting her with her daughter.

Hailey and Jo bond over what inspired them to become cops. Jo mentions that her first memory is of her mother trying to drown her, and Hailey says she wanted to be better than her father.

Jo asks Hailey to take her back to rehab.