He's trying to get by while studying under the G.I. Bill. His debut concert with Maestro Tosca keeps getting postponed, and his girlfriend Jane is antsy, and her brother John offers him a factory job. But he hurts his hand on a machine after only three weeks on the job, and quits rather than risk his hands. And he has to postpone his concert again.
Humiliated by John at Jane's birthday party, he disappears. Jane tracks him down thanks to Maestro Tosca, who says Carl "... is the most talented young man I have met in twenty years, and I am going to present him in a concert as soon as I can!"
Carl's playing piano at a dive bar when Jane finally finds him, and wouldn't you know it immediately catches on fire, forcing them both to the roof. John heroically carries Jane and slides down a wire to the ground, risking slicing open his hands to save her.
One happy ending later, Jane is saved, Carl's hands aren't hurt too bad, his concert is postponed but actually happens, everybody loves him, the end.