1935. As Europe prepares itself for a calamitous war, six homicidal lunatics - the so-called 'Devil's Six' - are confined in a remote castle asylum in rural Czechoslovakia. Each patient has their own dark story to tell, and Dr Viktor Kosárek, a young psychiatrist using revolutionary techniques, is tasked with unlocking their murderous secrets. At the same time, a terrifying killer known as 'Leather Apron' is butchering victims across Prague. Successfully eluding capture, it would seem his depraved crimes are committed by the devil himself. 

As Jan Fabel, of the Hamburg murder squad, interprets this twisted imagery at a crime scene, it becomes clear that each new crime is a grisly reference to folk stories collected by the Brothers Grimm. The hunt is on for a serial killer who is exploring the darkest, most fundamental fears hidden in ancient fairy tales.

Two high profile victims - a former left-wing radical turned environmental campaigner and a geneticist researching the possibility of inherited memory - are found murdered within 24 hours of each other. Both men have been scalped. Jan Fabel and his murder team have nothing to go on other than a single red hair left as a signature at each scene - each hair cut from the same head at least 20 years previously. Connections begin to appear: a long disbanded terrorist group; a mummified body; and a killer....

Glasgow, 1932. When the son-in-law of one of the city’s wealthiest shipbuilders is found floating in the River Clyde with his throat cut, it falls to Inspector Jimmy Dreghorn to lead the murder case - despite sharing a troubled history with the victim’s widow, Isla Lockhart. From the flying fists and flashing blades of Glasgow’s gangland underworld, to the backstabbing upper echelons of government and big business, Dreghorn and his partner ‘Bonnie’ Archie McDaid will have to dig deep into Glasgow society to find out who wanted the man dead and why.

Calcutta, 1923. When a Hindu theologian is found murdered in his home, the city is on the brink of all-out religious war. Can officers of the Imperial Police Force, Captain Sam Wyndham and Sergeant Surendranath Banerjee track down those responsible in time to stop a bloodbath? Set at a time of heightened political tension, beginning in atmospheric Calcutta and taking the detectives all the way to bustling Bombay, the latest instalment in this series presents Wyndham and Banerjee with an unprecedented challenge. Will this be the case that finally drives them apart?

Just as a major environmental summit is about to start in Hamburg, a massive storm hits the city. When the flood waters recede, a headless torso is found washed up. Initially, Jan Fabel fears it may be another victim of a serial rapist and murderer who stalks his victims, then dumps their bodies in waterways around the city. But the truth of the situation is far more complex. Fabel’s investigations lead him to a secretive environmental Doomsday cult called “Pharos”, the brainchild of a reclusive, crippled billionaire.

After an incident makes remaining in Glasgow impossible, Police Sergeant Don Colyear is sent to work in a remote Highlands town. His new Inspector wants him gone and the locals wonder why he’s even there. Still, Don makes a go of things, striking up a good working relationship with rookie officer Rowan Forbes. As Don starts to investigate petty crimes, it soon becomes clear that there is something off about the town. A string of teenage disappearances has not been given due attention. 

Jan Fabel is a troubled man. His relationships with the women in his life are becoming increasingly complicated. If that weren’t bad enough, after a gap of ten years, a female serial killer – the Angel of St Pauli – again makes the headlines when an English pop star is found in Hamburg’s red-light district, dying of savage knife wounds.

Kim and Mia Timmers were just 11 years old when they were imprisoned in a local psychiatric institution, accused of murdering the man they believed to be responsible for the death of their family. Now, 10 years later, they are due for release. Detective Pieter Vos is given cause to reopen the case when the girls disappear. His investigation takes an unexpected turn when it becomes clear that someone is posing as Little Jo - Kim and Mia's other sister, who was killed along with their parents.

Lennox liked Quiet Tommy Quaid. Perhaps it's odd for a private detective to like - even admire - a career thief, but Quiet Tommy Quaid was the sort of man everyone liked. Amiable, easygoing, well dressed, with no vices to speak of - well, aside from his excessive drinking and womanising, but then, in 1950s Glasgow those were practically virtues. And besides, throughout his many exploits outside the law, Quiet Tommy never once used violence.

A Cologne detective asks Jan Fabel for his help in tracking down the Carnival Cannibal, a terrifying serial killer who kills at the start of the world-famous annual Carnival. Unknown to anyone, Fabel's deputy, Maria Klee, also heads for Cologne to hunt down a different, even more dangerous killer - one with whom she has a score to settle. Taras Buslenko, a Ukrainian special-forces commander, prepares his undercover unit for a "black" operation into Cologne.

When a light aircraft crash-lands at Machrie airport, Daley and Scott rush to the scene. But it soon becomes clear that both occupants of the plane were dead before take-off.... Meanwhile, tending to his lobster creels, Hamish finds himself in the wrong place at the wrong time, and back at the County Hotel, Annie is beginning to suspect her new boss Ian Macmillan may not be as he first appeared. 

Detective Sergeant Washington Poe is in court, fighting eviction from his beloved and isolated croft, when he is summoned to a backstreet brothel in Carlisle where a man has been beaten to death with a baseball bat. Poe is confused - he hunts serial killers and this appears to be a straightforward murder-by-pimp - but his attendance was requested personally, by the kind of people who prefer to remain in the shadows. As Poe and the socially awkward programmer Tilly Bradshaw delve deeper into the case, they are faced with seemingly unanswerable questions.

A year after a calamitous blunder by the Russian secret service left a British citizen dead from novichok poisoning, Diana Taverner is on the warpath. What seems a gutless response from the government has pushed the Service's first desk into mounting her own counter-offensive - but she's had to make a deal with the devil first. And given that the devil in question is arch-manipulator Peter Judd, she could be about to lose control of everything she's fought for.

Jan Fabel is a haunted man. Head of the Polizei Hamburg's Murder Commission, Fabel has dealt with the dead for nearly two decades, but when a routine enquiry becomes a life-threatening - and life-changing - experience, he finds himself on much closer terms with death than ever before. Two years later Fabel's first case at the Murder Commission comes back to haunt him: Monika Krone's body is found at last, 15 years after she went missing.