When a teenage boy is abducted from a Dundee street in broad daylight, DS Vicky Dodds and her team are put on the case. The drowned body is found with just one clue—an inscrutable code scratched onto his arm. Vicky must hunt across Dundee for the brutal killers, drawing on old friends and family to probe the deep corners of the dark web and Scottish gangs. As Vicky learns to doubt who she can trust, she connects with a new friend, someone who can maybe help her resolve her own murky past.