At first, Fingers refuses to believe that his Granddad has gone barking mad! But what straight-thinking grownup goes around LICKING the postman, growling like a dog and chasing hospital security guards up trees? And when Fingers and his sister Sally discover a bizarre machine in Granddad's workshop, mix-ups turn into mind-swapping madness-one look at Granddad's dog DaVinci is proof of that!
