Superintendent Runcorn of Scotland Yard is spending Christmas on the wild and beautiful island of Anglesey.  While out on a walk he discovers the body of Olivia Costain, the local vicar’s sister.  Only an outsider could have committed such a heinous crime, he is assured, but as he delves deeper into Olivia’s past, he uncovers some disturbing secrets, and opens the door to a new future for himself...