A barber, Buzz Curtis (Abbott), and a porter, Abercrombie (Costello), work for a Hollywood salon. It is from there that they are sent to an agent's, Norman Royce, office to administer a haircut and shine. On the way there they run into a former co-worker, Claire Warren who is about to star as the lead in a new musical. At the same time, her co-star Gregory LeMaise, whose fame is dwindling, arrives and invites her to join him at lunch. She declines, which angers him.
While at the agent's office, Buzz and Abercrombie witness LeMaise enter and declare to Royce that he cannot work with Claire. Royce, who has just seen a young singer, Jeff Parker, audition fires LeMaise and offers the job to Parker. This causes LeMaise to change his mind, and Royce does as well, giving LeMaise his job back.
Later, Abercrombie and Buzz figure out a way to get Jeff into the part: they were planning to have Abercrombie provoke LeMaise and then he would have to punch him while Buzz took a picture of it with his camera to have the evidence, so they could throw LeMaise in jail. They find LeMaise on his boat and they board before it starts floating around the sea. Abercrombie insults and provokes LeMaise (purposely as that was part of the plan) to the point of LeMaise punching Abercrombie but unintentionly as part of the plan, Abercrombie then falls overboard and is feared drowned.
After LeMaise leaves to call the police, Buzz discovers that Abercrombie had survived. But they decide instead that pretending Abercrombie was dead, killed by LeMaise the killer, was "better than Abercrombie getting socked". So Buzz hides Abercrombie as LaMaise comes out and then declares that he murdered Abercrombie and then the police sought him out and they believe Buzz's story after questioning LeMaise. But LeMaise escaped and is now noted as a fugitive killer before he could be thrown into jail, and Jeff is giving the role in his place.
After their successful plan, Abercrombie puts on a big fake beard on as well as a turban to diguise himself as he goes out with Buzz to opening of the film. Buzz goes in to watch the success of the film with Kavanaugh while Abercrombie goes to meet him in a bar afterwards. But, suddenly, LeMaise appears, after Abercrombie takes off his disguise. Learning that Abercrombie is alive, LeMaise chases Abercrombie around the whole backlot. After a long and hailarious chase, LeMaise is eventually caught and thrown into jail (even though everyone knew then that Abercrombie wasn't dead, since Kavanaugh couldn't afford another set just to put LeMaise into the part whether or not Abercrombie was dead) and Claire and Parker become famous when the film is successful and Buzz and Abercrombie become bigtime agents in Hollywood, while LeMaise is left in jail for the rest of his life.