One for sorrow, two for joy. Edinburgh is gripped by the greatest terror it has ever known. A lone bomber is targeting victims across the city and no one is safe. Three for a girl, four for a boy. DCI Ava Turner and DI Luc Callanach face death every day - and not just the deaths of the people being taken hostage by the killer. Five for silver, six for gold. When it becomes clear that with every tip-off they are walking into a trap designed to kill them too, Ava and Luc know that finding the truth could mean paying the ultimate price. Seven for a secret never to be told. But with the threat - and body count - rising daily, and no clue as to who's behind it, neither Ava nor Luc know whether they will live long enough to tell the tale.