Hisano is a withdrawn high school girl who lost both her parents at a young age. She now lives with her father's second wife and that wife's family - all people who aren't related to Hisano. She has periodic hallucinations of a sheep whose condescending mockery sets her on edge.
One day she meets a mysterious boy to whom she feels a strange attraction...but that boy may be connected with a vaguely-remembered tragedy from her past...