One detective driven by duty and remorse.
Six cousins bound by a secret pact.
A shocking and unforgettable conclusion.

Amid the backdrop of WWII, a double murder taking the life of two cousins and disguised as a boating accident has occurred on the Devon coast. Due to new evidence, Mary Ainsworth, mother of one of the victims, hires a seasoned and retired Metropolitan police officer to travel to her home from London and investigate. She grants him a week to solve the murders before handing the evidence over to the local police.

While there, the tenacious detective, Sean Lloyd, who is troubled about a past tragedy, becomes immersed in a dark web of household secrets implicating the remaining four cousins.
Will the detective be able to solve the crime before the allotted time and before the murderer strikes again?