It's 1969. Five years ago, teenager Alexandra Tozer was murdered. Her sister, Helen Tozer, will never forget. Returning home after quitting the Met Police, she brings with her the recovering Detective Sergeant Cathal Breen, who slowly becomes possessed by the unsolved case. But Breen is on a trail, for the two men connected to this case met in Kenya, during the Mau Mau uprising; and the history that Britain has turned its face from is now returning to haunt it.

Marylebone, November 1968. Detective Sergeant Breen has a death threat and two burned bodies on his hands. One is an un-mourned vagrant; the other the son of a politician. One case suffers the apathy of the police; the other obstructed by a PR-conscious father. Then the potential perpetrator of his death threats is murdered. Banished from a corrupt system, Breen is finally forced to fight fire with fire.

An unidentified cadaver is found in a freezer in an unoccupied luxury house. No-one seems to know or care who it is or who placed it there. When DS Alexandra Cupidi is handed the case, she can have no idea it will lead her to a series of murderous cover-ups and buried secrets. Namely the discovery of the skeleton of public-school boy, Trevor Wood, beneath a housing development. 

Police Sergeant William South has a reason for not wanting to be on the murder investigation. He is a murderer himself. But the victim was his only friend - like him, a passionate birdwatcher. South is warily partnered with the strong-willed Detective Sergeant Alexandra Cupidi, newly recruited to the Kent coast from London. Together they find the body, violently beaten, forced inside a wooden chest. Only rage could kill a man like this. South knows it.

London, October 1968. As Beatles fans encamp outside Abbey Road Studios up the road, the Marylebone CID is as much an old boys' club as it ever was: comfortably sexist, racially prejudiced and crawling with corruption. Detective Sergeant Cathal Breen is the pariah of the office, having just run out on a fellow officer held at knifepoint, when it's shaken up by the arrival of WPC Helen Tozer: awkward chatterbox, farmgirl, and the first woman to enter the murder unit - apart from the secretary.

Spain, 2020. When expat fugitive Jack Cleland watches his girlfriend die, gunned down in a pursuit involving officer Cristina Sanchez Pradell, he promises to exact his revenge by destroying the policewoman. Cristina's aunt Ana has been deaf-blind for the entirety of her adult life: the victim of a rare condition named Usher Syndrome. Ana is the centre of Cristina's world - and of Cleland's cruel plan. John Mackenzie - an ingenious yet irascible Glaswegian investigator - is seconded to aid the Spanish authorities in their manhunt.

Was the biggest case of his career the worst mistake he ever made? Ten years ago, DCI Jack Logan stopped the serial child-killer dubbed "Mister Whisper", earning himself a commendation, a drinking problem, and a broken marriage in the process...When another child disappears a hundred miles north in the Highlands, Jack is sent to lead the investigation and bring the boy home. But as similarities between the two cases grow, could it be that Jack caught the wrong man all those years ago?

She always went to far. DS Alexandra Cupidi has done it again. She should have learnt to keep her big mouth shut after the scandal that sent her packing - resentful teenager in tow - from the London Met to the lonely Kent coastline. Murder is different here, among the fens and stark beaches. She was the one who found the killers. The man drowned in the slurry pit had been herded there like an animal. He was North African, like many of the fruit pickers that work the fields. The more Cupidi discovers, the more she wants to ask - but these people are suspicious of questions. 

Detective Inspector Avison Fluke is a man on the edge. He has committed a crime to get back to work, concealed a debilitating illness and is about to be made homeless. Just as he thinks things can't get any worse, the body of a young woman is found buried on a Cumbrian building site. Shot once in the back of the head, it is a cold, calculated execution. When the postmortem reveals she has gone to significant expense in disguising her appearance, Fluke knows this is no ordinary murder.

Investigating how a severed hand ends up on the third green of a Cumbrian golf course is not how Detective Inspector Avison Fluke has planned to spend his Saturday. So when a secret protection unit from London swoops in quoting national security, he's secretly pleased. But trouble is never far away. A young woman arrives at his lakeside cabin with a cryptic message: a code known to only a handful of people, and it forces Fluke back into the investigation he's only just been barred from.    

Aidan Poole logs on to his laptop late at night to Skype his girlfriend, Zoe. To his horror, he realises that there is someone else in her flat, and Aidan can only listen to the sounds of a violent struggle - and then the chilling sound of silence. Aidan is desperate to find out if Zoe is OK. But then why is he so hesitant to call the police? When his messages finally reach them, DCI Jonah Sheens and his team take the case - and discover the body.

A city torn apart. Glasgow, 1969. In the grip of the worst winter for years, the city is brought to its knees by a killer whose name fills the streets with fear: the Quaker. He takes his next victim - the third woman from the same nightclub - and dumps her in the street like rubbish. A detective with everything to prove. The police are left chasing a ghost, with no new leads and no hope of catching their prey. DI McCormack, a talented young detective from the Highlands, is ordered to join the investigation. 

A serial killer is burning people alive in the Lake District's prehistoric stone circles. He leaves no clues, and the police are helpless. When his name is found carved into the charred remains of the third victim, disgraced detective Washington Poe is brought back from suspension and into an investigation he wants no part of. He is reluctantly partnered with brilliant but socially awkward civilian analyst Tilly Bradshaw, and the mismatched pair uncover a trail that only he is meant to see. The elusive killer has a plan, and for some reason Poe is part of it.

This is a fact: Ryan Summers walked into Three Rivers College and killed 13 women, then himself. But no one can say why. The question is one that cries out to be answered - by Ryan's mother, Moira; by Ishbel, the mother of Abigail, the first victim; and by DI Helen Birch, put in charge of the case on her first day at her new job. But as the tabloids and the media swarm, as the families' secrets come out, as the world searches for someone to blame...the truth seems to vanish.

Meet the Skelfs: well-known Edinburgh family, proprietors of a long-established funeral-home business, and private investigators.... When patriarch Jim dies, it's left to his wife Dorothy, daughter Jenny and granddaughter Hannah to take charge of both businesses, kicking off an unexpected series of events. Dorothy discovers mysterious payments to another woman, suggesting that Jim wasn't the husband she thought he was.