Rover is a neighborhood dog who replaces Fatty in a baseball game after he makes his sixth error. Rover turns out to be a good ballplayer, and is spotted by a casting director who is watching the game while a flat tire is being repaired. The casting director thinks Rover is a good candidate for a film he is currently involved in and gets the gang to bring Rover in for a screen test. However, neither the filming director nor the gang can coax Rover to bark on cue, and the dog doesn't capitalize on his big chance to be a movie star. While at the studio, Rover is made to appear to talk by Professor Ventriloko.