When Ruby (Leelee Sobieski) and her younger brother Rhett’s (Trevor Morgan) parents, Grace and Dave Baker, are killed in a car crash, their parents’ best friends, Erin and Terry Glass (Diane Lane and Stellan Skarsgard), become their guardians.

It seems there’s nothing to be afraid 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.