Erykah Macdonald has a nice life, the kind you're supposed to want. But on her twentieth wedding anniversary, she's about to cross a line.

Several hundred miles away in the shallow waters of a Hebridean island, a body is found and it's clear this is no accidental death.

Erykah has to make an irreversible choice - she's used to living with secrets but there are far worse secrets about to emerge. From a morgue in the Highlands to the powerplays in Westminster, a net is tightening. And those that find themselves caught will kill to get out.

Erykah must decide what she's capable of. She should be scared - but sometimes, crossing the line is the first step to freedom...