The Giant Diamond Robbery

I, Geronimo Stilton, am no sportsmouse. But that didn't stop Grandfather William from dragging me to a golf tournament so I could be his caddie! Once I arrived, who should I bump into but my friend Kornelius Von Kickpaw, a.k.a. Special Agent 00K. Someone was plotting to steal the Super Mouse Cup, and it was up to me and Kornelius to crack the case!