After the third trumpet player in a radio station orchestra falls asleep during a lulling coffee commercial, he dreams he is the angel Athanael, third trumpet player in the heavenly orchestra. One day Athanael is summoned to the Department of Small Planet Management. There, the Chief tells Athanael that conditions on Earth are so bad that the planet must be destroyed and that Elizabeth, the Chief's receptionist, has persuaded him to send Athanael, with whom she is in love, to blow the horn that will signal the end of the world. The Chief instructs Athanael to blow the horn exactly at midnight as no other time will produce the desired effect and warns him that two other angels, Osidro and Doremus, who failed to blow the horn as instructed, now live on Earth as fallen angels. Carrying the special trumpet, Athanael descends to Earth through a hotel elevator. Osidro and Doremus recognize Athanael as he leaves the elevator and, realizing that the end is near, plan to prevent him from blowing his horn. Meanwhile, dapper jewel thief Archie Dexter plots with Fran, the hotel cigarette girl, to steal a strand of pearls belonging to Lady Stover. When Fran bungles the job, Archie coldly tells her he no longer loves her, and Fran retreats to the roof, where she contemplates suicide. Athanael is also on the roof, waiting for the stroke of midnight, but misses the moment when he stops Fran from committing a sin by jumping off the building. Now that Athanael is a fallen angel, he auditions for a jazz band and is booed off the stage. After he stops in a café for a meal, he is forced to leave his trumpet in lieu of a cash payment. In the meantime, Elizabeth persuades the Chief to allow Athanael a second chance. The Chief permits Elizabeth to join Athanael and tell him the news. On Earth, Elizabeth wins five dollars in a contest and gives the money to Athanael so that he can redeem his trumpet. When Osidro and Doremus learn that Athanael has another chance to blow the horn, they offer Archie $10,000 to steal the trumpet. While Archie and Fran distract Elizabeth and Athanael, Humphrey Rafferty, Archie's associate, unsuccessfully attempts to steal the trumpet. After several complications, the Chief arrives on Earth, and determined to fulfill his assignment, Athanael grabs the trumpet and rushes to the roof. Warning the others to keep their distance, Athanael accidentally falls off the roof. The others grab him, but during their attempt to pull him up, they also fall over the edge. While dangling at the end of a chain of people, Athanael drops into a huge coffee cup that is part of an advertisement. He hears the clock strike midnight and is about to blow his horn when he tumbles out of the coffee cup and wakes to discover that he has been dreaming the entire event. He then tells Elizabeth, who plays the harp in the orchestra, that his dream was so crazy that if they made it into a movie, nobody would believe it.