Lennie finds old Miss Butterworth in the run-down toffee works and is told the dreadful story of Clum, the toffee monster created by old Mr Butterworth in Victorian times.
When Cyril, Anthea, Robert, Jane and their baby brother go digging in the gravel pit, the last thing they expect to find is a Psammead an ancient Sand-fairy!
Electra is having a brilliant time playing scary tricks on all her mermaid friends and when Sparkle, the baby seahorse, joins in they have even more fun.