After the stepmother and two aunts of ten-year-old violin prodigy Ronald Kimball settle their lawsuit regarding his custody, they agree that he can go to Hollywood to make a film provided that the studio allows him time for his lucrative radio broadcasts and recordings. After the guardians forbid Ronnie to play football with the studio "Wee Kids Company," drain the swimming pool and order him to practice the violin, he locks his instructor in a closet and escapes out a window. The instructor thinks that Ronnie has been kidnapped, and subsequent radio reports say that the Gollenger gang is suspected. Meanwhile, Ronnie makes friends with a dog, goes swimming and acquires the nickname "Scrapper" after hitting a bully. Ronnie next meets Duke, the likable bagman for the Gollenger gang, who tells Ronnie he is a G-man, and he helps Duke fix a flat tire. While they drive to Pinecrest Lodge, where Duke is to bring a satchel of money to the gang, radio reports about Ronnie convince Duke that the kid is "hot" and they part. Ronnie finds Duke's wallet, and when Duke hits railroad president Benjamin P. Robbins' car, he pays for the damage with money from the satchel. Ronnie rides with a policeman to Pinecrest, where he makes friends with Tom Cotter and his sweetheart Jean, Robbins' daughter. Meanwhile, Robbins' chauffeur is arrested for using the money he received from Duke. At the lodge, Ronnie calls home, and although one of the gang members hangs up the phone, the call is traced. Police and Ronnie's guardians fly to Pinecrest and arrive with men investigating the chauffeur's bill, which is from a Chicago registered mail robbery. During a fight, Duke, who tries to protect Ronnie, is shot. Ronnie then shoots Gollenger in the hand with a slingshot, and Robbins and Tom join in. After the gang is captured, Ronnie cries as Duke is carried out. The guardians then promise Ronnie that the pool will be filled and that he can play with the studio kids.
