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.

When a battered suitcase containing the dismembered body of a young man washes up on the shore of the river Thames, Detective Erika Foster is shocked. She's worked on some terrifying cases but never seen anything like this before. As Erika and her team set to work, she makes the link with another victim - the body of a young woman dumped in an identical suitcase two weeks ago. Erika quickly realizes she's on the trail of a serial killer who's already made their next move.

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.

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 young boy discovers the body of a woman beneath a thick sheet of ice in a South London park, Detective Erika Foster is called in to lead the murder investigation. The victim, a beautiful young socialite, appeared to have the perfect life. Yet when Erika begins to dig deeper, she starts to connect the dots between the murder and the killings of three prostitutes, all found strangled, hands bound, and dumped in water around London.

One dark winter’s morning, bride-to-be Cara Dunne is found hanging in her home, dressed in her wedding dress, with a lock of hair removed. Detective Lottie Parker is first on the scene. Looking at Cara’s bruised and battered body, she wonders who could have hated her enough to kill her at the happiest time of her life. The case takes a darker turn that afternoon with another shocking discovery - the broken body of a second young woman, pushed from the roof of the hospital where she worked. Fiona Heffernan was also due to be married....

A crime wave has hit town. The target is a highly sought-after brand of streetwear called Hybird X, clothing that costs a fortune and resells for unbelievable prices. Houses are burgled, kids mugged on the streets...and finally a young man dies, all for the sake of his shoes. Then another boy’s body is found in a pile of rubbish. Meanwhile illegal steroids are flooding the streets. And there are dark movements on the marshes. 

One hot summer evening, 11-year-old Mikey Driscoll is on the way home from playing with friends. Two days later, his body is discovered on a bed of wildflowers by some local teenagers. The case is assigned to Detective Lottie Parker, and this time it’s personal. The victim was a close friend of her son, Sean, from the run-down Munbally estate on the other side of town. Sean tells his mother Mikey was behaving normally before he died, but Lottie can’t help but feel that her son is keeping something from her.

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.

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.

Erin is a documentary filmmaker on the brink of a professional breakthrough, Mark a handsome investment banker with a bright future. They seem to have it all - until Mark loses his job and cracks start to appear in their perfect life. But they’re determined to make it work. They book their dream honeymoon and trust that things will work out - after all, they have each other. Could the life of your dreams turn out to be a nightmare?  

Deep in the muddy fields of the Lincolnshire Fens, a teenage girl is found wandering, delirious, claiming to have been drugged at a party. Metres away, the drowned body of another girl is found on an isolated beach. And all this on a small stretch of land where, nearly 10 years ago, the shocking disappearance of a young girl remains an open case.

When Amy Whyte and Penny Brogan leave a nightclub in the early hours of Sunday morning and don’t arrive home, their families are beside themselves with worry. Conor Dowling has just been released from prison, a man full of hatred for Amy, the girl who put him behind bars in the first place. The case is given to Detective Lottie Parker when the girls’ blood-soaked bodies are found, days later, in a derelict squat. Chillingly, both girls are clutching silver coins in their hands - what message is this killer leaving behind? All the signs point to Conor, but his alibi is watertight.

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.

The young woman standing on Lottie's step was a stranger. She was clutching the hand of a young boy. "Help me," she said to Lottie. "Please help me." One Monday morning, the body of a young pregnant woman is found. The same day, a mother and her son visit the house of Detective Lottie Parker, begging for help to find a lost friend.