There's a witches' convention going on in Newquay and it's the decision of the Grand High Witch (Anjelica Huston) to use an evil potion (via sweet shops) to turn the children of Britain into mice. This is a truly delightful children's film in which real mice and 'mice' from Jim Henson's Creature Workshop blend almost seamlessly as the battle between good and evil maintains a fevered pace. Huston is magnificently malevolent.