Casey is having a hard time adjusting to his new role, and so does Severide. Things come to a head when they disagree with which approach to take on a rescue call. Severide is upset that Casey doesn't seem to listen to him, interpreting his friends actions merely as a way to assert authority, and Casey assumes that Severide is jealous of his new position. Casey tries to get Boden involved, but is told to handle things himself, because he might not like Boden's method of resolution. The first attempt to make peace just ends up worsening the situation, and when the two finally come to some sort of peace, it feels more like a mere detente than actual peace.
Kidd's suspicion of Hope intensifies when her paycheck is "lost" in transit. Kidd's complaints cause she and Brett to exchange some strong words -- Brett accuses Stella of disliking Hope because she slept with Kelly instead of Hope's job performance. Hope makes a big show of taking on the folks at payroll and getting Stella's check reissued. But by the time Stella gets her check and apologizes to Brett, Brett has her own suspicions about her childhood friend. She confronts Hope, who denies the allegations, but then shreds Stella's original check after Sylvie leaves.
Otis' latest toy is a firefighting robot from Japan that he signed up to beta test. The robot turns out to be rather unimpressive -- possibly because Otis can't control the thing as the app and instructions are in Japanese. Casey (already in a bad mood) has no patience for Otis' latest gadget or the discord that it brings to the firehouse. Even though Herrmann isn't a fan of "Rescue Pal," he comes to Otis' defense when he thinks Casey is being too hard on the most junior member of the team.
Sylvie goes on a date with a hot doctor she and Gabby meet on a call, but when they stop by his hospital later, she finds out he's married.