As Detective Dan Lockhart is called to a wealthy London street to investigate Natasha’s death, he’s startled by the similarity to a previous case. Noticing the cable-tie restraints and the tiny scratches on Natasha’s wedding finger, Dan already knows what he will find if he looks in her mouth - the metal ball which choked her to death. Months earlier, Kim Hardy was found in the same position in a run-down hotel across the city - an identical silver ball in her throat. But Kim’s murderer was caught and sent to prison - did they arrest the wrong man?

Five years ago, DCI John Lomond led the search for notorious Glasgow child-killer ‘The Sandman', until personal tragedy forced him off the case. In Lomond's absence, the killer was never found. Now, with nothing but work left in his life, Lomond remains obsessed with the case–despite the nightmares it brings. When a child is abducted in similar Sandman fashion from an affluent Glasgow suburb, Lomond is brought in to find them before it's too late.

It’s been five years since Detective Zac Boateng’s daughter was murdered, and her killer was never found. Now Zac is back working for the Metropolitan Police and is more determined than ever to bring the city’s killers to justice. When a man is found brutally murdered in a rundown south London shop, all fingers point to the highly intelligent and manipulative Darian Wallace. Two years ago, the victim helped send him to prison. And he’s just been released.

Freya loves her new home on a quiet suburban street. And her beautiful neighbor, Emily, is everything she’s ever wanted in a best friend. Finally, she has somebody to share her secrets with over a glass of wine. But as Freya watches her new friend setting the table for dinner one evening, she sees something shocking that makes her think that Emily’s life might not be as perfect as it seems. Days later, Emily and her daughter vanish.

Former CIA agent Ellen McGinley is battling to overcome PTSD when she stumbles upon a domestic terror plot. The deadly attack is due to take place in six days, one that will strike at the very heart of the country. But no sooner than she alerts the authorities, she finds herself locked in a psychiatric ward. No one believes her. She's the only one who thinks it's real. And she's the only one who can stop it.