When Ruby (Leelee Sobieski) and her younger brother Rhett's (Trevor Morgan) parents are killed in a car accident, their parents' best friends, Erin and Terry Glass (Diane Lane and Stellan Skarsgård), become their guardians. The Glasses promise Ruby and Rhett a world of opulence and California fun-in-the-sun to help them forget the nightmare they've just experienced. All they have to do is move into the Glasses' gated house in picturesque Malibu. It seems there's nothing to be scared of--until Ruby begins to suspect that Erin and Terry may not be the ideal guardians they seem. But are her suspicions justified, or merely the perceptions of a rebellious teen with a fertile imagination? Unless she's absolutely sure, Ruby shouldn't throw any stones . . . for what you don't see in the Glass house can kill you.