When a successful businessman is left for dead in a tenement close, police in Glasgow are flummoxed. Who could want him dead? His wife has a strong financial motive but the decoding of a mysterious inscription on his forehead points to a motive of revenge.

Then a second body is found, horribly mutilated, also bearing a message. DS Mark Nicholson and DCI Alex Scrimgeour fear they may have a potential serial killer on their hands. Their fears are realised when two more murders turn out to be connected.

Can Mark keep his mind on the job for long enough to work out how exactly these deaths are related to each other? He has enough worries of his own, what with juggling work, being a single parent to two-year-old Gus and now his boss Alex is edgy and distracted. He’s hiding something, but what?

With the help of DC Megan Webster, Mark vows to catch the twisted killer before they strike again but are they on the right path? Is the killer hiding in plain sight after all?