Mister Monday

Arthur Penhaligon is a boy who was supposed to die at a young age but is saved by a strange key shaped like the minute hand of a clock. The key opens a doorway to another realm, releasing bizarre creatures that bring a plague with them. A man named Mister Monday will do anything to get the key back, forcing Arthur to enter a mysterious house that only he can see to learn the truth about himself and the key. This is the first book in the Keys to the Kingdom series.