An alien spaceship crashes on Earth due to the powerful musical energy emanating from Group Sounds band The Tigers. The Tigers have to protect an alien princess who escaped from the ship and became obsessed with their lead singer Julie. Can they save the day by performing their megahit songs like "Mona Lisa's Smile" and "Seaside Bound"?

The Tigers, a rock band, escape their parents and teachers trying to forcibly cut their long hair, but accidentally stow away on a train to Tokyo. In Tokyo they get in some trouble, but eventually get jobs as musical assistants. Can they make the stage debut they've always dreamed of, or will their dreams be cut short?