Most people don't realise that an entire Ghost World exists alongside their own. They aren't aware that they walk with ghosts every day. Tom Golden is the only one who knows, the only one who can see them. He spend all his time with Invisible Friends, especially Arthur But then three extraordinary ghosts appear on the scene - ghosts who are visible to everyone! This could mean big trouble for the ghost world if humans suddenly remember that ghosts exist, but how can Tom stop the most powerful poltergeist, thesper and screamer?