Elf alert! - Susan Price

Alex Langford is used to the unusual. Since Olly Spellmaker, the mad, motorbiking witch, rode into his life, he's met a hairy boggart, a ghost that drips, and a wailing spirit called the Green Lady. So when Alex notices suspicious-looking, muddy little bootprints on the kitchen floor, he's prepared. But even he's shocked to discover that garden gnomes have invaded his house - through the cat flap! The gnomes claim they're earth-elves and demand the right to live on their ancestral land. Land which happens to have Alex's house built on it!

It's an Elf Alert - and Alex needs Olly Spellmaker's help! Surely she'll know how to perform an elf-eviction?