The story is based out of a little town in the heard of California, where two sisters await their most favorite time of the year - Halloween. The waiting and excitement, leads them to a home-adventure, which involves the arrival of an unexpected and unwanted guest - a monster. The monster has the effect of calming the kids and helping the mother. This book provides an introduction to the monster who becomes part of the family life, setting the background for later stories which would revolve around fun and scary engagement with the children.