Tilly and George shrink in size with the striking of the grandfather clock and in this adventure they meet up with and help a family of mice desperate to move from the house in which they have been living beneath the floorboards after a stray cat takes up residency. The children set off with the mice on an eventful journey, in which they meet Bitz - a scary, hairy bluebottle, Sloop - a kindly watervole, a vindictive and temperamental frog, not to mention several other interesting characters. Their journey takes them along fast-flowing rivers, through windswept sand dunes into captivity and finally freedom. Need I say more ........