Anarchy hits Dunedin when a cargo ship runs aground on Aramoana Beach amid a crowd of onlookers. One of them discovers a skull in the sand while desperate scavengers fight each other for the best of the bounty. Waking up to the chaos and hurrying outside to give the police a hand, Detective Constable Sam Shephard cops a wallop before her attacker is himself beaten senseless - and she saves his life in the ambulance. Returning to work, she is sent to help recover a body submerged in the water, the autopsy revealing that this was no accidental drowning but a lethal assault. The undercurrents from one morning's madness turn out to be far-reaching as Sam begins to tie events together. Who else will be caught in the backwash, with a killer on the loose? Can Sam stem the tide?