Tim is a keen young helper at Mr McMarvel's workshop, and he's desperate to learn how to make amazing machines. There's Rupert, (Mr McMarvel's robot,) the Unlock-Anything Machine, and the Grunts-Squeaks-and Scary-Noises Machine for starters. Not to mention the Extra-Fast-Rollerblading Machine (for people in a hurry) and the Dappled-Ice-Cream Machine (that needs fresh grass.)
But all is not well at the workshop. Tim is horrified to learn that Mr McMarvel is in trouble. Things get worse when creepy Max Fish comes to help out. Max has a diabolical plan, and it's all down to Tim, Rupert and the amazing machines to outwit Max, rescue Mr McMarvel and solve the problems in the workshop.