The last alarm (1926)

Firemen Tom and Joe each loves the other's sister, although neither is able to support a wife. Tom's troubles are compounded by a rival for his sweetheart's hand. In a drawn out fight he bests the rival, who steals the revenue from the firemen's ball (of which Tom is treasurer) and hides the money in the storage warehouse in which Tom's sister works as a stenographer. While Tom, Joe, and their sweethearts search for the money, the villain also returns for his loot, and, in his haste, he sets the building afire--trapping the foursome behind a steel door. Their calls for help reach the street, an alarm is turned in, firemen come to the rescue, and the money is found in a blazing desk.