Charley Maplewood is about to reach a milestone: He’s about to turn 10 — the big one-oh! He has never been one for parties — that would require friends, which he doesn’t have. Well, unless you count his monster friends, but they’re only imaginary. Charley’s still adjusting to his parents’ divorce and his move to a completely new school. Now that he’s turning 10, he decides to throw a birthday party for himself, complete with a “House of Horrors” theme. Of course, things don’t work out as he plans. Will Charley be able to pull it together before the big one-oh…becomes the big OH-NO!?