A detective and his zany pals take over a failing department store.

Singer Tommy Rogers wants to sell his half-share in Phelps department store, which he inherited from his adopted father, Hiram Phelps, and give the money to a conservatory of music for poor children. Unknown to Tommy, store manager Grover has been stealing from Phelps for some time and does not want to be found out, so he sends one of his cohorts to kill Tommy. When Tommy, who has worked out a deal for the Hasting Brothers chain to buy the store, is knocked unconscious in an elevator, his aunt Martha, who owns the other fifty percent of the store and is engaged to Grover, becomes concerned for his safety. Over Grover's objections, Martha decides to hire a private detective, and, after consulting the telephone directory, selects down-on-his-luck Wolf J. Flywheel. The eccentric Flywheel accepts her offer of $25 to take the case and promises anonymity. She then introduces him to Grover, saying that Flywheel is a new floor walker she wants to hire. Grover is suspicious of Flywheel, especially as he and Martha recite poetry to each other, but she soon admits that Flywheel has been hired to protect Tommy. Tommy is touched by her concern and agrees to let him be his bodyguard. He also hires Flywheel's jack-of-all trades assistant, Wacky, who turns out to be the brother of Tommy's friend Ravelli. Within a short time, Flywheel, Wacky and Ravelli have created chaos in the store and annoyed customers, much to Grover's irritation. The day before the sale is set to go through, Grover arranges for Peggy Arden, a woman with whom he is involved, to lure Tommy to a road house. Although she poses as an important music critic, Tommy refuses to meet her, thus foiling another of Grover's schemes. That same day, music department employee Joan Sutton, with whom Tommy is in love, happily tells her brother Chris that she and Tommy are now engaged. Chris, who has been one of Grover's cohorts, has a change of heart and tells Flywheel about the two thugs who are in the store to kill Tommy. As they are talking, the Hastings brothers enter the store and Flywheel mistakes them for the hired killers, but his error is quickly pointed out by Grover. By chance, Wacky and Ravelli catch the real killers when an elevator operator shouts "up!" and the criminals think that he is a policeman ordering them to put their hands in the air. With identities now established, Grover concocts another scheme and suggests that the final papers for the sale be signed after the store closes, when they can hold a ceremony for the staff and invite the press. During a photo session, the lights go out and Joan is kidnapped, so Flywheel, Wacky and Ravelli decide to develop the picture and see who took her. Tommy soon finds Joan and when Ravelli develops the picture, Grover is revealed as the culprit. Grover then sneaks up on them and demands the negative and photo at gunpoint. After a brief struggle, a wild chase through the store ensues, which involves a variety of conveyances, including roller skates and bicycles. Flywheel, Wacky and Ravelli eventually corner Grover and he is forced to admit his murder plot as cameramen are poised to take his picture and he knows that one of the cameras has been rigged with a hidden gun. Finally, Martha agrees to be engaged to her hero Flywheel, and as they enter his ancient car, it is repossessed,and they are towed away.