Grey Arthur finally knows where he belongs - at the side of Tom Golden - as his invisible friend.

He's been thinking that maybe there are other ghosts like him, who aren't very good at haunting and would make perfect invisible friends. And so the School for Invisible Friends begins ...

But where have all the good ghosts gone? Something very strange is going on and even things in the Real World don't seem right!

Faced with the prospect of losing Arthur, Tom realises that he not only needs his invisible friend, but that Arthur needs him too, and now, more than ever ...