In the midst of a rock festival, a charity worker is sliced across the stomach. He dies minutes later. In a crowd of thousands, no one saw his attacker. The following week, the body of a primary school teacher is found in a Dumpster in an Edinburgh alley, strangled with her own woolen scarf. DI Ava Turner and DI Luc Callanach have no motive and no leads - until around the city, graffitied on buildings, words appear describing each victim.

On a remote Highland mountain, the body of Elaine Buxton is burning. All that will be left to identify the respected lawyer are her teeth and a fragment of clothing. In the concealed back room of a house in Edinburgh, the real Elaine Buxton screams into the darkness…. Detective Inspector Luc Callanach has barely set foot in his new office when Elaine’s missing persons case is escalated to a murder investigation. Having left behind a promising career at Interpol, he’s eager to prove himself to his new team.

It's DS Logan McRae's first day back on the job after a year off on the sick, and it couldn't get much worse. Three-year-old David Reid's body is discovered in a ditch: strangled, mutilated and a long time dead. And he's only the first. There's a serial killer stalking the Granite City, and the local media are baying for blood. Soon the dead are piling up in the morgue almost as fast as the snow on the streets, and Logan knows time is running out. More children are going missing. More are going to die.

Toby is a happy-go-lucky charmer who's dodged a scrape at work and is celebrating with friends when the night takes a turn that will change his life - he surprises two burglars who beat him and leave him for dead. Struggling to recover from his injuries, beginning to understand that he might never be the same man again, he takes refuge at his family's ancestral home to care for his dying uncle Hugo. Then a skull is found in the trunk of an elm tree in the garden - and as detectives close in, Toby is forced to face the possibility that his past may not be what he has always believed.

It is a cold January morning and Shetland lies buried beneath a deep layer of snow. Trudging home, Fran Hunter's eye is drawn to a vivid splash of colour on the white ground, ravens circling above. It is the strangled body of her teenage neighbour Catherine Ross. The locals on the quiet island stubbornly focus their gaze on one man – loner and simpleton Magnus Tait. But when police insist on opening out the investigation a veil of suspicion and fear is thrown over the entire community. For the first time in years, Catherine's neighbours nervously lock their doors, whilst a killer lives on in their midst.