On the heels of Casey's brush with death, he and Dawson officially announce their relationship to Firehouse 51 - to the surprise of absolutely no one. Even Mills is happy for them - although it's bittersweet considering his and Dawson's past. There's no time to celebrate, though, as Dawson begins her first day training as a firehouse recruit. Her nerves peak during orientation when she learns there's only one other woman in her class - Rebecca Jones. And she's smart, fearless and trains with a swagger. Looks like Dawson's got some competition.
At 51, Shay grapples with her new ice-queen EMT partner Rafferty, who all but ignores Shay even after an insane call to a botched, back-alley plastic surgery. When Shay confronts her about the cold shoulder, Rafferty gives it to her straight - she's not a fan of Shay's "lifestyle." If that wasn't enough, Boden informs Shay that an attorney wants to interview her about the suicide she witnessed. This sends Shay into an emotional tailspin that coincides with the attorney's arrival at the firehouse. Shay hides and begs Rafferty to cover for her; to Shay's amazement, she does. Maybe they've found some common ground...
Speaking of, Clarke continues to grumble through his suspension as Chicago P.D. investigates his role in the Hayes murder. Despite Detective Halstead's plea to come clean, Clarke stays firm. CPD plays another card and brings in Mills for a chat, showing off phone records that prove Clarke's wife cheated on him with Hayes and when Hayes ended it, she got jealous. Mills expresses as much to Clarke in person, but he wants to hear it from Lisa herself. She, of course, denies the accusation - but has trouble looking Clarke in the eye. That's all the answer he needs - no longer able to cover for Lisa, Clarke returns to Halstead with his true, airtight alibi.
A call sends the team out to a precarious wreck - a wrought iron pole has burst through the windshield of a car and impaled the still-conscious driver. Casey promises the panicked driver a six-pack if he can make it out alive and keeps the guy calm while they use a blowtorch to free him from the pole. But Casey's steady hand betrays him once he's alone - turns out he can't remember the combo to his locker. Is this a holdover from his traumatic injury? He breaks off the lock in secret and replaces it. Yet, when Dawson asks about his recovery, Casey lies and changes the subject, suggesting they move in together. New place, new start.
Herrmann and Otis contend with the same mantra when a notification sends them reeling: paperwork indicates they don't own Molly's. The bank does. With the bar now in limbo, Otis welcomes an unlikely distraction - Severide's half-sister, Katie. She flirts with him at the firehouse and they bond over the board game Settlers of Catan. Are they nerd-perfect for each other? Nothing like a friendly game to find out - and sure enough, sparks fly and they share a tender kiss.
During another training exercise, Dawson notes Jones' attraction to their teacher - Severide. He doesn't seem to mind when she invites herself along on Truck, but Severide bristles at a disparaging comment she makes regarding a fellow recruit and he tosses her out of the academy. Or so he thinks - turns out her family's connected to CFD, so Severide must rescind his directive. Jones isn't going anywhere.
A call sends everyone to a fire in progress. When the squad arrives, they get hit with a major surprise - bank robbers! The squad's taken hostage and the room fills with smoke as the fire grows in strength. Gasping for air, everyone bails one by one... except Casey and the gunman. Enraged, Casey tackles him and beats him - losing his grip on reality. Mouch pulls Casey away, now concerned for his lieutenant's well-being.
With everyone safe and back at the station, Boden makes a big announcement: Mills is officially on the squad! The celebration kicks off at Molly's and only one person misses it - Casey. He shows up at the hospital where he visits the victim from the wrought iron rescue. As promised, he pulls out a six-pack and they share a beer, both happy to be alive.
Dawson faces an uphill battle - and unlikely competition - as a new recruit at the academy. Meanwhile, Casey discovers a lingering injury and Mills receives life-changing news.