Take away pizza, a suspicious broken leg and a marathon mystery that has even Rastamouse puzzled. Scratchy has been training hard for Da Big Cheese Marathon, but Rubba (who does no training at all) always seems to beat her. Rastamouse is curious when Rubba claims his twin brother Dub has broken his leg, and the mystery intensifies when they find Dub shooting hoops in his backyard. A rapidly recoved broken leg seems too strange and Rubba's purchase of identical sets of trainers and two identical running kits has Rastamouse questioning whether Rubba is cheating to win.