Firehouse 51 continues to battle the inferno at the mattress factory when an explosion happens. Brett, Foster, and Chief Boden fall through the ceiling as the roof collapses, and Brett injures her arm. Otis gets trapped outside the vault and is badly burned.
Otis is taken to the hospital for treatment but succumbs to his injuries while Cruz gives a tearful goodbye to his best friend.
The episode then jumps forward three months after the fire. Cruz worries who will remember Otis in a few years when everyone at 51 has gone their separate ways. To ensure Otis' memory lives on, Boden unveils a monument in memoriam of the fallen firefighter at the end of the episode.
Casey comes under fire for the call he made during the mattress factory fire -- he requested Brett and Foster come into the building to treat the victims -- and faces an inquiry from the City Safety Committee regarding the incident. The committee wants to hold someone responsible, and Boden steps up and takes the blame during the inquiry. Afterward, Boden tells Casey he has been cleared of all wrongdoing.
Brett has moved to Indiana with fiancee Kyle and gets a job as a full-time paramedic at her hometown fire department in Fowlerton. After her interview, she runs into her former best friend Hope, who wants to make amends. Brett tells Kyle she is unsure about the job at the fire department. Kyle tells her she doesn't have to work if she doesn't want to and can just be a chaplain's wife.
Hermann yells at Ritter for not listening to his orders during the mattress fire and freezes the candidate out for the next three months. Ritter eventually apologizes to Hermann for disobeying him, and Hermann says Ritter will be back on engine once Casey finds a replacement on truck.
Chad Collins replaces Brett as the new paramedic at 51, and Foster isn't happy about her new partner. Mouch recognizes Collins and later realizes the new paramedic is an underwear model.