Merry lives a simple life on the Isle of Wight. For work, she creates cryptic crosswords.

For pleasure, she swims in the ocean's cold embrace. In between, she keeps an eye on her neighbour, Lucas Manning, son of her late best friend Julia. Until one day, Lucas disappears.

The Manning family has always had a sinister side - only Lucas has been above suspicion. Until now. And with Lucas's employers desperate to find him and the sensitive project he has absconded with, has Merry been wrong about Lucas all along?

As her search for Lucas unfolds, Merry suddenly has to confront her own dark past.

And as the tangle of her life story rises to the surface, Merry is about to find a twist she never expected.