DI Jon Spicer’s investigation into the vicious slaying of a Russian asylum seeker grinds to a halt when the man’s identity turns out to be false. It seems the only truth to his story was the fact he was found drifting off the British coast in a small boat.

Before the man’s true identity can be discovered, more asylum seeker start to die – each murdered in the same horrific way. By the time Spicer realises what links the men, he knows there’s a trained assassin at large who’s desperate to guard a secret of enormous magnitude. And when he ignores MI5’s warnings to back off, Jon also realises, too late, he is now the target of a man whose sole purpose is to kill.

And all the while, a series of heartbreaking and enigmatic messages are being found drifting in from the sea – slowly revealing the horrific plight of a group of refugees trapped on a raft.