One October morning, high school junior Bryan Dennison wakes up a different person-helpful, generous, and chivalrous-a person whose new admirable qualities he doesn't recognize. Stranger still is the urge to tie a red sheet around his neck like a cape. Bryan soon realizes this compulsion to wear a red cape is accompanied by more unusual behavior. He can't hold back from retrieving kittens from tall trees, helping little old ladies cross busy streets,...