Steve Rogers and Bernie Rosenthal go out for a night on the town, dancing at the Roseland Ballroom and dinner at a fine restaurant, and a carriage ride around the park; Steve is having trouble with old memories reminding him how much older than Bernie he is. [During these idyllic events, we see and arsonist spreading gasoline downstairs in an apartment building.] While Steve and Bernie have a nightcap at her apartment, suddenly the building across the street explodes in flames. Bernie calls 911 while Steve dashes upstairs, dons his Captain America togs, and slides on a wire to the top floor of the burning building. He rouses all of the tenants and stay behind to search for others. While rescuing an unconscious couple, the roof falls in on him and he is overcome by smoke; a pair of firemen enter via the window and one carries Cap to safety just before the floor collapses under him. When he recovers he is told that the fireman who carried him out, Sam Douglas, is dead.
In a nearby bar, the arsonist is being berated by his employer who didn’t want anyone harmed in the blaze; he is a real estate developer who wanted the building destroyed so he could buy up the block cheaply. The arsonist doesn’t care and thinks that fatalities would be a benefit to the developer’s scheme….
Back at Steve’s place, Mrs Kappelbaum is having a dinner for Mike Farrel, who was a firefighter at the previous evening’s blaze but he is too distraught over his teammate’s death to be good company. Knowing other buildings on the block could also be targeted for arson, the police set up a patrol in the streets, while Cap does the same from the rooftops. That night, Cap is attacked by a villain in a heavy flame protective suit that shoot fire and energy beams out of the wrists. While battling the Blockbuster, Cap loses his balance and falls though the roof of a warehouse below; the baddie sets the structure aflame. Cap breaks through the pier beneath and escapes via the river; he comes up behind Blockbuster and topples him into another warehouse. There is a cat-and-mouse chase and battle throughout the building and Blockbuster gets Cap in a bear hug with his enhanced strength; Cap planned this though and smashes the control pack on his back. The suit immediately loses its air filter, air conditioner, and strength enhancing abilities so that the arsonist cannot save himself from the approaching fire. Cap extracts him from the suit and carries him to safety. Mad for revenge the baddie pulls a gun to shoot Cap but the firemen knock him for a loop with a blast from the fire hose.
Cap talks to a police captain who tells him that the arsonist will probably be granted clemency if he informs on his employer. It’s not justice but it will have to do. An epilogue reveals that is what did happen.