Courtney Crumrin grumbles about everything, but now she's really got something to grumble over. Having run out of credit cards, her parents are moving to the wealthy suburb of Hillsborough, to live rent-free with their creepy old uncle Aloysius. Courtney is now an outcast among her rich, snobby classmates.

And if that weren't bad enough, the musty, decrepit old mansion that she now calls home is occupied by stranger creatures than just her parents or Uncle Aloysius. They crawl about the house, just out of sight. They crunch bones in the corner. They climb up on the bed and watch Courtney while she sleeps. Mom and Dad don't notice them, but Uncle Aloysius calls them the Night Things.