Does anyone smell acetone?

Okay, we'll admit that this episode of Chicago Fire was a little better than some of the others this season have been.

There was at least some cohesiveness and a theme, and we got a few moments that suggested what may lie ahead for the rest of the season.

On Chicago Fire Season 12 Episode 9, we zeroed in on a few distinct relationships: Chief Boden and James, Violet and newcomer Rosie, and Mouch and a strange patient from the Paramedicine program named Kathy.

Others on the cast got minimal screen time throughout this episode except for Severide and Van Meter, who worked together to solve an arson case with some twists and turns.

Having been on for more than a decade, this show has explored tons of relationships. But none have been quite so captivating as the bond between Chief Boden and his stepson, James.

Not that people should get cookies for stepping up and parenting kids whose parents they marry, but there's something to be said for a man who stays committed to a kid after he's no longer with his mom.

James realizes that he's way in over his head with his mom's house. He's ashamed of the mess he's gotten himself into after renting to friends who are taking advantage of him.

There's a nice moment where he confides in Kylie, who is exceptionally kind to him (no surprise there). He's hesitant to talk to Boden because he doesn't want Boden to think of him as a loser.

To everyone's great shock, Boden comes through for James and shows up for him without even being asked.

(That's a joke. No one was shocked.)

James: I can't believe you drove all this way.
Boden: I was worried about you, son.

• Permalink: I was worried about you, son.

After Lennox's exit last week on Chicago Fire Season 12 Episode 8, we've wondered who would replace him as Violet's partner on the ambo. It looks like we've got our answer.

Rosie is new, and Violet is unsure about her. She naturally had some questions about Rosie's background. Rosie quickly explained away Violet's questions by casually dropping the bomb about her affair with her married anatomy instructor.

Um, what? Read the room, Rosie.

Violet: What kind of drama did you get into at Lakeside?
Rosie: Oh, you know, the kind where you get busted for hooking up with your anatomy instructor and then everyone blows a gasket.
Violet: No, like, really, what happened at Lakeside?
Rosie: Oh no, that happened.

• Permalink: What kind of drama did you get into at Lakeside?

As the episode progresses, Violet and Rosie (wait — how cute are their names together?!) spend more time together, and it seems like they're going to butt heads.

Violet seems to think Rosie is unfocused and inexperienced and has valid concerns about whether Rosie can handle the job.

Well, the joke is on Violet. During an outrageously stressful call where a child has a gun pointed at the two of them, Rosie manages to keep the kid calm (while he has a loaded gun in her face!) so Violet can work on a kid with a gunshot wound.

This is the first time we're seeing Rosie in action, and we have to say, we're pleasantly surprised. She's clearly got some crisis management training, which will serve her well on the team. (Oh, and Violet saves the other kid, thank goodness.)

Now for the really fun part — Mouch has a stalker!

Fine, that's not really fun, but honestly, it was a great storyline to watch play out. Mouch is such an entertaining character, and we love watching him get into shenanigans.

This time, he got more than he bargained for when a patient from the Paramedicine program started full-on stalking the poor guy. The bond between them seems to be more on the patient (Kathy)'s side, but Mouch is too lovely to hurt her feelings.

That is until things escalate, and he's forced to kick her out of the station. Spoiler alert: she doesn't like that. But we're glad it happened anyway because of how that ended.

It's no secret that Trudy has always been a badass, but watching her come in and take Kathy down while Mouch stuttered through an apology for being rude to her was incredible.

Girl power, am I right?!

Anyway, that was amazing, and I'd sign up to watch an entire episode of just Trudy rescuing men in distress. What a rush.

They like to pack a lot of action into these episodes, but one thing that we don't want to leave out here is the moment when Severide goes back to find the rapper who was falsely accused of burning down the music studio.

Severide is a stand-up guy. That's why he was so badly missed during his hiatus. But seeing him go out of his way to take Antoine's music files to him was nice. He didn't have to do that, but it was a kind gesture.

It seemed like it might have been Severide's way of apologizing for suspecting Antoine of arson in the first place.

As an honorable relationship mention, watching Van Meter and Severide work together was cool, too. It wasn't anything super entertaining, but they're a friendly, awkward team. They're like the world's most reserved buddy cop team.

There's a bit of a shorthand between them that is enjoyable, at least.

All in all, it was a decent installment. It's always amazing to see how much these writers can pack into a one-hour time slot. We'll be excited to see how things progress for Rosie and Violet, as well as James and Boden.

Also, will Violet and Carver stop playing games, or what? Time will tell, I guess.

Let us know in the comments how you felt about the episode and what you think about the season so far.

Haley Whitmire White is a staff writer for TV Fanatic. You can follow her on X.