When a young man drowns after a boisterous party in a small riverside town, his friends and family report it to the Kings Lake police as a devastating accident.

DC Smith, newly returned from leave, and the young, ambitious trainee Christopher Waters are assigned to the case as a routine investigation. But the post-mortem reveals violent injuries, witnesses give contradictory accounts of the events leading up to the drowning and locals seem determined to redirect their attention.

Becoming increasingly suspicious of institutional caution and external interference, Smith and Waters strike out on their own. As they get closer to the truth, they realise the danger is not quite over.