Lily is chronically ill, but while her parents are welcoming a new baby she sneaks home from her grandmother's house and, aided by animal friends, combats the demons who have moved in.

Lily is used to hospitals--she's spent more time in them than out of them thanks to her recent health issues. But when her mother goes into labor, her parents drop her off at her grandmother's house and rush to the hospital without her. Lily doesn't want the new baby to replace her and she certainly doesn't want to be sick anymore. Most frustrating of all, she forgot to pack Willo, her favorite toy. Under her grandma's not-so-watchful supervision, Lily sneaks back home to get Willo. Expecting to find an empty house, she is surprised to find her parents there. But something isn't right... They look just like her mom and dad until she gets closer and sees their coal black eyes. And they refuse to let her in--it's their house now. With the help of some surprising new friends that she meets in her garden, Lily is determined to beat these shadowy replacements and be reunited with her real parents. But is she strong enough to triumph?