Violet and Carver are giving off vibes, which Ritter knows right away. Violet says it wasn't a big deal, and she's not on the market.

Cruz is acting lieutenant again. He's feeling good. Cruz sees Casey and Brett's wedding invitation, but as Herrmann asks him about it, it seems like he didn't receive one.

Gibson brings his A game for his first firehouse breakfast.

Stella and Kelly are doing OK during his absence, but he's been kicking around moving to OFI. She's good with it, but she still seems unsure.

Brett's sitter quit last night, and Julia comes to the firehouse. She apologizes to Boden, but he's already got a big smile on his face. When she gets a call, Capp and Tony take over.

Smoke is coming from the garage in the back of a house. A patio is on fire. The owner is glad to see them, and they arrive just in time to rescue her from the roof falling in. Carver grabs the gas. She has no clue what could have started it. Then, there is a sound from inside the garage. A little girl is hiding inside a cabinet.

Harper is the woman's daughter. She didn't like her mother being on the phone. Stella asks her how it might have started, and the girl's mother stops her. It could have been a freak accident, after all. But Harper likes Stella, so she might want to see her again.

Stella's instincts say something is off, but Herrmann says all of his kids started fires, and none of them went to jail.

Tony and Capp are building a cage for Julia because they can't keep her in one place. Capp has his wedding invitation, and Tony admits he was the one who helped Brett with the paper, which they all think is so cool.

Casey and Brett want Boden to officiate at their wedding. He's honored.

Boden gets a text from his stepson, James. He's outside. It's an awkward reunion. James is in from out of town. He didn't know where to go. Boden assures him they can figure out whatever it is. It's not James; it's his mom. She's in jail.

Border patrol found tons of fentanyl in her trunk. James says it's a guy named Dion who did it to her. She could get three to five years. Boden makes a call to Mike Knolls.

Truck is training, but Kidd isn't paying close attention. Harper had a former burn mark on her coat. It's probably not her first time. Gibson says girls aren't usually firebugs. Carver recalls a 17-year-old who begs to differ. Gibson discovers that there were three small fires in the last two weeks. They head off to investigate.

The girl's mother is named Alicia. She's coming home, rushing into the house, and when there, she locks the door. Mouch wonders if they should call social services, but everyone agrees it's too time-consuming and unlikely to be greeted well.

If Shonda had the goods on Dion, she would have gotten a better deal. Knolls tells Boden a federal case like this is a long, expensive ordeal. Boden will do it for James.

They lose Julia again. They find her in the radio room with Herrmann.

The next call is from a parking garage. Some guy thought he was putting on the parking brake, but he stepped on the gas. His friend's legs are sticking out from under the car.

Carver and Violet tease each other into another tryst tonight.

Stella is heading out to investigate Harper. Carver offers to go with her, but she's got this.

Brett gives Cruz kudos for his fast work at the scene of the accident. As she rooted around in her bag, he thought she was going to bring out his invitation. When she doesn't, he leaves the invitation question open.

Stella visits Van Meter for advice, and he says he's happy Severide stayed in the ATF program.

Boden visits Shonda. She seems embarrassed that he's there. She did it. Dion didn't even know. She's guilty.

Boden and Herrmann talk about guilt and doing anything you can to protect your child.

Then, Alicia visits Kidd at the firehouse. She has no idea what this could do to her family. If her ex-husband finds out what's happening with Harper, he'll use it to get custody.

Kidd doesn't care. If Harper seriously hurts someone or herself... Alicia can't lose Harper, so please let me handle it, she says.

Boden is left to share Shonda's news with James, breaking his heart. Boden said she swears it's the first time she ever did something like this, and he believes her. James lashes out. If he didn't want to help, he could have just said so. After all, he left them long ago.

Cruz thinks he's not invited to the wedding because they once dated. Capp wonders if he asked her.

Sylvie is called away and hands Julia to Cruz.

The call is Alicia and Harper's house. The fire is raging. Alicia screams for help before jumping out the window.

They're searching the house, looking for Harper. They find her under the sink in the bathroom. She says it was an accident and apologizes. They find her, but Stella's leg falls through the floor, hampering her exit. She gives Harper to Gibson and tries to freeze herself as her alarm signals.

Harper screams for her mother, who is being loaded into the ambulance. it doesn't look good.

Kidd and Severide are texting when Boden gives her an update about Alicia. it was touch and go, but she'll likely pull through.

Everyone is playing with Julia. As Carver plays her, Violet has a look on her face that Ritter recognizes.

When Cruz sees a floater received an invitation, he finally has to check with her. She doesn't even know who Mulligan is. It's right next to his locker. She put it in the wrong one! She laughs that he seriously thought he wasn't invited.

The paper on the invitation has a fire edge.

James is outside Boden's place. He doesn't blame Boden, and Boden apologizes for not being there for him, reminding him that this is his home, too.