Seven days. Four deaths. One chance to catch a killer.

Sixteen-year-old Robert arrives home late. Without a word to his dad, he goes up to his bedroom. Robert is never seen alive again.

The discovery of a body on the coast of the Scottish Highlands plunges Detective Inspector Monica Kennedy into a murder investigation that won't begin and end with one death.

Meanwhile, seventeen-year-old Nichol has been missing for seven days. His last message was to social worker Michael, who can't quite shake the suspicion that something is terribly wrong.

As Monica is faced with catching a murderer who has been meticulously watching and waiting, Michael keeps searching for Nichol, desperate to find him before the killer claims another victim.