The Fourth Alarm (1930)

Following in his father's footsteps, Dick Turner becomes a fireman, but he breaks his leg in a firetruck-auto collision with wealthy, speed-crazy Helen Griffith. They fall in love during his stay in the hospital, and Helen's father sees in this development a perfect opportunity to keep secret his clandestine manufacture and storage of nitroglycerin by having Dick appointed fire inspector. The upstanding lad puts duty before love, but his report is countered by an accusation of solicitation of bribery. Just then, a fire breaks out in Griffith's warehouse; Dick is detailed to the station house, but he finally bolts to the fire in time to rescue Helen, who was trapped in a storeroom.