In Bushi's school, the big kids are called Bullfrogs. They love to pick on the little kids like Bushi, who are called Guppies. One day, a tough Bullfrog named Yag-yu starts pouring soda on Bushi. When Bushi accidentally spills the soda all over Yag-yu's uniform, he knows he'd better run - and fast! With the Bullfrogs charging behind, he ducks into the doorway of a karate school, where he sees a black belt hanging on the wall. A sign below says, "This belt belonged to the Master. He was a small man with a big heart and the spirit of a tiger."

Bushi can't resist trying the belt on, but it is too long and he trips and hits his head. When Bushi awakens, he discovers he has gone back in time. He's about to learn the lesson of a lifetime, courtesy of two samurai, a dangerous bandit, and the wise Master of the long-ago karate school. This exciting adventure story will intrigue and fascinate young readers and will give heart to anyone who's ever been threatened by a bully.