Geronimo Stilton is invited to a rat-jitsu martial arts championship in a snowy faraway land, much to the famous reporter's surprise. With his helpful relatives Thea, Trap, and Benjamin, Geronimo goes to cover the event for the Rodent's Gazette. But something strange is happening. After each championship match, the winner disappears without a trace! Will Geronimo get involved and solve the mystery of the missing martial artists? Or will he be consumed with fear and race back to New Mouse City with his tail between his legs?