Sam appears to be a model teenager: he's an affectionate son to single mum Jenny and stands up to bullies at school. But Jenny is protecting him from a dark secret, and when new girl Chrissy arrives in town, Sam's suppressed violent desires start to emerge.

With the death at the hospital causing suspicion, Sam must tread carefully and hold his desires in check. As a threat from the past resurfaces, Jenny summons the courage to face her fears.

When Sam exposes Jenny's dark secret her world begins to unravel. Sam comes face to face with his father and Jenny finally begins to understand her son's true nature.

With Sam's father released from prison, Jenny makes a desperate effort to get to the bottom of Sam's increasingly dangerous behaviour. But is she too late?