Dawson catches Jones cheating on a written academy test and struggles to keep it to herself, even after Jones explains she suffers from dyslexia. Casey recommends Dawson stay mum, but she's not convinced - that is, until she panics during a routine exercise and none other than Jones swoops in to save her. When it's clear Jones will keep Dawson's slip-up to herself, the two look like they're headed toward friendship... but Dawson's competitive side returns when Severide reveals that Jones received a higher grade than she did on the written test.
Back at the station, Shay finally faces the lawyer she dodged earlier and is stunned by the news - Darryl Bell, the man she witnessed commit suicide, left his entire trust to her, a total worth about $40,000. Shay, uncomfortable accepting the money, instead intends to turn it over to Darryl's brother, Jed, who seems nice enough when they meet at Darryl's apartment. However, Clarke discovers Jed's been diverting Darryl's military pension to himself, meaning the brother's basically a criminal - something Shay learns firsthand when he confronts her about the trust in the parking lot. Wary, Shay reconsiders her decision to give Jed the money, but remains unsure what to do with the large sum...
After an apartment fire triggered by an indoor propane grill almost kills someone, Boden discovers the entire complex lacks suitable heat - the tenants must jerry-rig their apartments to stay warm in the subzero winter temperatures. He seizes the moment to drop in on the landlord and issue a stern warning to fix the situation. This leads to an unexpected station visit from one of the tenants, Donna. She brings Boden thanks in the form of butternut squash puree - and a little flirtation. With Mills' urging, Boden drops by Donna's apartment under the guise of fixing a cabinet. She invites him in for dinner, and it looks like a little romance might be underway...
Meanwhile, as the newest official member of the squad, Mills keeps a lookout for the time-honored tradition of pranking the newbie. A Sun-Times reporter seems to fit the bill when he shows up unsolicited, eager to interview Mills for a feature. Certain the reporter's a fake, Mills toys with him, feeding him casual jokes. But later, he discovers the reporter is the real deal, and the man refuses to conduct another interview with him. Will Mills' off-the-cuff comments bring unwanted heat to the station?
Stealing a private moment with Severide, Casey admits to suffering memory loss - specifically the two days before the accident. He pleads with Severide to help write the accident report from that night, and Severide agrees, even though Casey admits he hasn't told Dawson anything about the lingering injury. But the jig's up when one of Casey's angry episodes occurs during a dinner with Dawson at a swanky restaurant. Later, he plays it like it's no big deal, and when Dawson calls him on it, he again assures her everything's okay.
With Mills officially on squad, there's an opening available for station cook - a position everyone agrees fits Katie to a tee. Especially Otis, who, despite Shay's warning to lay off, takes the opportunity to ask Severide for permission to date his sister. After a tense pause, the lieutenant agrees, and Otis grins ear to ear.
An intense escalator rescue leads Shay and Rafferty to the local hospital where Shay discovers Rafferty recently worked as a resident - until her fiancée died of Hodgkin's disease. Later, in private, she bonds with her new partner over their shared traumas, and the two hug, friends at last.
Another alarm sends the squad to a rooftop downtown and a photographer stuck in a smokestack. The rescue proves tricky, but also presents Mills with his first true save. He stays calm and secures the man to the harness, and Severide helps lift them to safety. Boden gives a triumphant nod to Mills - he's a real member of the squad now.
The bank calls Otis back about the extension on the deadline for the restaurant loan - denied. Since Molly's will be closed sooner rather than later, they decide to throw one last party to celebrate. The bittersweet mood's in full swing when Mills, still paranoid about the forthcoming newspaper story, spots a familiar face at the bar - the Sun-Times reporter. Turns out it was a prank after all, and the man is friends with Mouch. The laughter gives way to another announcement, this time from Shay: she's giving the money to Molly's!
Casey continues to deny his lingering injuries; Shay receives stunning news about Darryl's suicide; Dawson struggles to keep a damning secret.