Grieving mother Rosalie Douglas refuses to accept that her son Rob's sudden death was an accident. Husband Luke has moved out of the house, and teenage daughter Maddie is acting out, wracked with grief and an as-yet unexplained guilt over her brother's death. Their lives change for ever when Rosalie meets Jed - a charismatic young man - at bereavement counselling.

Rosalie is left reeling from her last encounter with Jed, and still struggling to deal with intrusive thoughts. She arrives home to something of an ambush when Luke admits he wants Jed to move into Rob's old room while he is away. Later, Maddie spirals further out of control, and Rosalie is torn between protecting herself from temptation and keeping Maddie safe.

Rosalie tries to secure some time away from Jed as his advances intensify to alarming new levels, and Maddie begins to see the darker, more frightening side he has been concealing. As Rosalie traces Jed's past, she unearths a series of increasingly disturbing discoveries - but nothing can prepare her for the truth she is about to uncover.