At lunch together, Shay and Severide discuss their upcoming move and Renee's baby. Shay questions the due date, not convinced that the baby's his, but Severide dismisses her as just jealous. Later, the firemen descend on a burning two-story house that explodes into an inferno. A collapse sends Severide to the basement and a daring rescue saves his life. But outside the building, he notes the address - 1751. His badge number...
Back at the firehouse, Boden makes an announcement: due to budget cuts, the city shut down Firehouse 33, and Firehouse 51 could be next unless they institute some uncomfortable changes. Everyone reels as he explains the new rules - no overtime, shared lockers - directives straight from Gail McLeod, the city's no-nonsense consultant.
This leads to more news - two firemen from 33, Spellman and Clarke, will join the house, a move that shifts Mills from Truck to Rescue. As Mouch and Herrmann bristle about how the current union president will react to these changes, they spot a car on fire outside the station - Severide's. And this time there's no doubt - it's arson and Severide's the target.
Casey sneaks in a spare moment to buy a round of drinks for Heather Darden on the anniversary of Andy's death, an event that still weighs heavy on their minds. Another bittersweet celebration occurs across town as Mouch sends off his Japanese girlfriend Mari. Although she prophesizes his greatness, Mouch struggles to believe her until he returns to the station and spots a campaign poster for the union president. He tears it in half and announces his candidacy - just as the alarm sounds.
Another residential fire blazes away, this time across two midrise buildings. The flames jump to the second floor, trapping Shay and Dawson as they tend to an unconscious woman. Casey and Severide use a ladder to bridge two windows and, as the fire rages on behind them, Dawson, Shay and the victim carefully inch across to safety. Afterwards, Clarke, the latest addition to 51, discovers an apparatus in the building - the same kind that ignited Severide's car.
At Molly's, Herrmann, Dawson, Otis and Cruz watch yet another group of patrons exit in favor of Game Day, the bustling sports bar across the street. Can they compete with that place? Even Cruz admits that Game Day's super fun - he has the photos to prove it.
That night, Gail McLeod summons Clarke to CFD headquarters and assigns him a difficult task: to be her secret insider at Station 51. He resists until she blackmails him, leaving him without a choice. Meanwhile, another call brings the squad to the scene of a serious collision involving a DUI... and a car Casey immediately recognizes. He sprints across the street to the handcuffed culprit - Heather Darden. Before police drive her away, she pleads with Casey to watch her two young boys, Griffin and Ben.
While Severide faces a dangerous arsonist, Firehouse 51 takes on new blood and new rules to avoid shuttering its doors due to budget cuts.