Plot
In Brooklyn, New York in 1920, 6-year-old Georgia Nolan aspires to be a fireman like her father used to be, before he retired to become a tailor. When Shawn tells her women aren't allowed to be firemen, Georgia pretends to give it up and follow in his footsteps as a seamstress, but secretly begins training on her rooftop alongside her faithful Dalmatian sidekick Ember.
Ten years later, in 1930, Mayor Murray asks Shawn to end his retirement to head up a young team of firefighters to combat a serial arsonist who is burning down the city's theaters with a strange purple fire and has somehow kidnapped all the city's other firefighters. Wishing to help and determined to prove herself to her father, Georgia disguises herself as a man named Joe and joins the team.
While in disguise, "Joe" meets the other firemen: Jinn, a Chinese who loves to drive fast as a cheetah but suffers from narcolepsy, and Ricardo, a muscular Spanish-American with a passion for chemistry and physics who can analyze the source of the fire. With training, the three become an effective unit, able to counter each other's inexperience and weaknesses with their own strengths.
By the time they determine the cause of the blaze - an impressive chemical in a glass ball triggered by music - only one concert hall remains. Despite being blocked off, an African-American diva named Laura Devine has been repeatedly breaking in to rehearse her upcoming musical. When asked to leave, she refuses, talking about how her childhood in the Jim Crow south taught her to never take no for an answer. When she demands her assistant Pauline haul her into the air for another round of practice, the crank handle breaks, sending her crashing into the floorboards.
"Joe" talks with Pauline. Seeing another woman discouraged about her career, she unmasks herself and tells her to go after her dreams. Unfortunately, Pauline is later fired by Devine and seemingly dies in the next blaze.
After suspecting first Devine and then the mayor, Shawn and "Joe" uncover the truth - the mayor and Devine are secretly dating because she's ashamed of being seen in public with a politician. The true arsonist is Pauline, a frustrated chemist and special-effects artist who has decided to burn the city down in revenge for her many insulting and sexist rejection letters. They also find all the missing firefighters, who have been hypnotized by the chemicals.
Triumphantly, "Joe" tells her father her true identity, but he still refuses to let her become a firefighter, admitting that she is actually the child of a couple he couldn't save in a fire 16 years ago. He'd promised to always look after her and keep her safe, and if she became a firefighter, he couldn't keep his promise.
After facing down Pauline's final act of vengeance, Shawn and Ember release the hypnotized firemen while Georgia goes to deal with Pauline. Pauline tries to get Georgia to join her in taking revenge, but she refuses - her father meant well, and the fire in her heart burns for saving people, not hurting them.
After Pauline gets arrested, Georgia and Ricardo become firefighters, while Jinn returns to driving a cab and hints that he hopes Shawn might let him ask Georgia out someday. As the end credits roll, various pictures and historic facts about real-life female firefighters are displayed, including the fact that they weren't paid until 1982.
