On a cold icy morning, a mother wakes to find her daughter’s blood-soaked body frozen to the road. Who would carry out such a horrific killing on the victim’s doorstep? Straight off her last harrowing case, Detective Erika Foster is feeling fragile but determined to lead the investigation. As she sets to work, she finds reports of assaults in the same quiet South London suburb where the woman was killed. One chilling detail links them to the murder victim - they were all attacked by a figure in black wearing a gas mask.

He's your perfect date. You're his next victim. When the tortured body of a young woman is found in a dumpster, her eyes swollen shut and her clothes soaked with blood, detective Erika Foster is one of the first at the crime scene. The trouble is, this time it's not her case.

When Detective Erika Foster receives a tip-off that key evidence for a major narcotics case was stashed in a disused quarry on the outskirts of London, she orders for it to be searched. From the thick sludge the drugs are recovered, but so is the skeleton of a young child. The remains are quickly identified as seven-year-old Jessica Collins. The missing girl who made headline news 26 years ago.

Detective Erika Foster is on a late-night walk near her new house in Blackheath when she stumbles upon the brutal murder of Vicky Clarke, a true-crime podcaster. Erika is assigned to the case and discovers that Vicky had been working on a new podcast episode about a sexual predator who preys on young female students around South London, staking out his victims in their halls of residence before breaking in at the dead of night.

In the dead of a swelteringly hot summer's night, Detective Erika Foster is called to a murder scene. The victim, a doctor, is found suffocated in bed. His wrists are bound and his eyes bulging through a clear plastic bag tied tight over his head. A few days later, another victim is found dead in exactly the same circumstances. As Erika and her team start digging deeper, they discover a calculated serial killer - stalking their victims before choosing the right moment to strike.

When a 19-year-old boy, Jamie Mills, is found hanging from a tree in a local park, his death is ruled a suicide. Detective Kim Stone’s instincts tell her something isn’t right—but it’s not her investigation, and her temporary replacement is too busy waiting for the next big case to be asking the right questions.

Kate Marshall was a promising young police detective when she caught the notorious Nine Elms serial killer. But her greatest victory suddenly turned into a nightmare. Traumatized, betrayed, and publicly vilified for the shocking circumstances surrounding the cannibal murder case, Kate could only watch as her career ended in scandal. Fifteen years after those catastrophic events, Kate is still haunted by the unquiet ghosts of her troubled past. Now a lecturer at a small coastal English university, she finally has a chance to face them.

Criminology academic Kate Marshall is on a scuba jaunt with her son when they dive toward a shocking discovery: the body of a teenage boy entangled below the surface of the Shadow Sands reservoir. The detective chief inspector’s too-quick narrative of a tragic drowning doesn’t add up, and when Kate follows the evidence, it leads to a darker discovery. 

Kate Marshall’s fledgling PI agency takes off when she and her partner, Tristan Harper, are hired for their first big case. It’s a cold one. Twelve years before, journalist Joanna Duncan disappeared after exposing a political scandal. Most people have moved on. Joanna’s mother refuses to let go. When Kate and Tristan gain access to the original case files, they revisit the same suspects and follow the same leads - but not to the same dead ends. Among Joanna’s personal effects, Kate discovers the names of two young men who also vanished without a trace.

One moonlit night, the bodies of two young people are discovered lying entwined on a blanket in the woods. The young man is clutching a red rose. It appears to be a lovers' suicide pact.... Until Detective Nikki Galena and DS Joseph Easter look more closely. Romeo and Juliet, as they decide to call them, were murdered somewhere else and brought to the woods. But why? Then another young couple are found dead, again beautifully posed as lovers. 

Kate Marshall was a promising young police detective when she caught the notorious Nine Elms serial killer. But her greatest victory suddenly became a nightmare. 15 years after those catastrophic, career-ending events, a copycat killer has taken up the Nine Elms mantle, continuing the ghastly work of his idol. Enlisting her brilliant research assistant, Tristan Harper, Kate draws on her prodigious and long-neglected skills as an investigator to catch a new monster. But there's much more than her reputation on the line: Kate was the original killer's intended fifth victim....

When Isabel Gallagher is found murdered on the floor of her baby’s nursery by her mother, it’s a grueling case for Detective Lottie Parker. Isabel’s pajamas have been ripped, her throat cut and an old-fashioned razor blade placed in her hand. As Lottie looks at the round blue eyes and perfect chubby cheeks of Isabel’s baby daughter, she can’t understand who would want to hurt this innocent family.

Detective Joseph Easter's daughter discovers a cottage hidden in some trees on a large fenland farm. Someone has been living there. The farm owner's wife has been receiving sinister pagan artifacts, including a witch's knife. Are they some sort of warning or message? Joseph and his daughter search the cottage and find an old satchel. Inside are photos of a beautiful girl, Jennifer Cowley. She went missing 15 years ago. She'd been stalked by a young man, who was convicted of her murder, even though her body was never found.

When 25-year-old Beth Mullen returns home, expecting to find her twin Rachel waiting for her, the silent house sends a shiver down her spine. She races upstairs to find her beautiful beloved sister cold in her childhood bed, her sparkling blue eyes closed forever, the morning after attending a glittering party.... Newly engaged Detective Lottie Parker knows that Rachel has been murdered the minute she enters the bedroom. Rachel’s neck is bruised and a shard of glass placed in her throat. Confronted with such a horrifying killing, Lottie wastes no time in pursuing every clue. 

Revellers are flocking into Greenborough for the yearly Dark Greenborough Festival, a three-day event celebrating local folklore, superstition, and the darker side of life. What the public doesn't know is that there has been a warning sent to the police, saying that Greenborough will be a very dangerous place this year. The anonymous letter ends with the Latin phrase, Mors certa, hora incerta: Death is certain, the hour uncertain.