Sam grew up in the shadow of the secret state. Her father was an undercover agent, full of tall stories about tradecraft and traitors. Then he died, killed in the line of duty.

Now Sam has travelled to Hoy, in Orkney, to piece together the puzzle of her father's past. Haunted by echoes of childhood holidays, Sam is sure the truth lies buried here, somewhere.

What she finds is a tiny island of dramatic skies, swooping birds, rugged sea stacks and just four hundred people. An island remote enough to shelter someone who doesn't want to be found. An island small enough to keep a secret...