The story takes place on a river. Kids love haunted houses, so just put it anywhere. Okay, we'll put a haunted house on an island, in the middle of the river. That's good, great. And we need space ships.
Space ships are good.
Go ahead, have some more coffee. I want to hear about the space ships. Space ships are good, kids love space ships. Or maybe just one, we can only afford one, I think. It lands on the haunted house.