Late on midsummer's night there is a splash in the river Thames. A body is found on an island, asphyxiated and laced with strange markings. For DCI Craig Gillard it's a baffling case. The victim's identity is elusive, clues are scarce and every witness has something to hide. Meanwhile one of Britain's deadliest serial killers is finally up for parole after a deal to reveal the location of two missing bodies. The felon has his own plans to get even with witnesses, accusers and the officer who caught him 30 years before. And who was that? A young trainee by the name of Gillard.

A young detective is out for a jog on a snowy winter morning. Then she sees something terrible: a murder in the park, sudden and inexplicable. A woman has been killed by a passing hooded cyclist. It’s just DCI Craig Gillard’s luck that he’s on duty. The body is that of Tanvi Roy, one of the richest women in Britain and matriarch of a food empire. With a tangled web of family and business contacts and jealousies, Gillard’s job just got even more complex. As he delves deeper into the Roy family, it’s clear that everything is not as it seems.

A large country mansion. A locked room. A gruesome murder. Russian oligarch Alexander Volkov has invited 1,000 guests to a party at his palatial Surrey residence, Westgrave Hall. But while giving a private tour of the library, a gunman kills Volkov, wounding his ex-wife and slaying her new beau. Nothing makes sense to DCI Craig Gillard. In the blood-spattered crime scene there are no forensic traces of anyone else involved, CCTV shows no one entered or left the library, and everyone seems to have an alibi.

A body is found on a quiet lane in Exmoor, victim of a hit and run. He has no ID, no wallet, no phone, and - after being dragged along the road - no recognisable face. Meanwhile, fresh from his last case, DCI Craig Gillard is unexpectedly called away to Devon on family business. Gillard is soon embroiled when the car in question is traced to his aunt. As he delves deeper, a dark mystery reveals itself, haunted by family secrets, with repercussions Gillard could never have imagined. The past has never been deadlier.

Promising architect Peter Young is shot dead at his desk. DCI Craig Gillard is on the scene, looking at what appears to be a brutal and highly professional hit: two bullets, fired with ice-cold calm. Gillard knows that the most crucial question in solving the crime is one word: why? Two weeks later, on the Lincolnshire coast, another body is found on a windswept beach. In this case there is no identity for the young man, just a curious brand burned into his neck....

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. 

As the mists roll over the fens and enigmatic lights twinkle in the distance, only the locals know their way along the hidden paths through the mysterious watery terrain of one of England's most beautiful and sometimes dangerous places. Detective Matt Ballard may have retired but there's still plenty going on in the fens to keep him busy. Someone trashes an old lady's garden and daubs her isolated cottage with hateful graffiti. Emilia Swain seems to be totally harmless, so why is she being targeted?

"And see if there's any news about the missing girl." Life, as Smith used to say, is just one thing after another - as one investigation ends, a new one begins. But for reasons unknown to the rest of her team, DCI Cara Freeman will be haunted by the next case for the Kings Lake Central murder squad. They find themselves delving into the seamy side of life in the town, and one of their number will have departed before this new investigation is over. Perhaps Detective Sergeant Chris Waters should have seen it coming, but he has a lot more than work on his mind these days.

In North Devon, where the rivers Taw and Torridge converge and run into the sea, Detective Matthew Venn stands outside the church as his father's funeral takes place. The day Matthew turned his back on the strict evangelical community in which he grew up, he lost his family, too. Now he's back, not just to mourn his father at a distance, but to take charge of his first major case in the Two Rivers region; a complex place not quite as idyllic as tourists suppose.

The gruesome double-murder at an Eastvale property developer’s luxury home should be an open-and-shut case for Superintendent Alan Banks and his team of detectives. There’s a clear link to the notoriously vicious Albanian mafia, men who left the country suspiciously soon after the murder. When Banks and his team find a cache of spy-cam videos hidden in the house, the investigation pivots to another violent crime that could cast the murders in an entirely different light.

As a massive storm batters the Scottish coast, Gordon Smith’s home is falling into the sea. The trouble is: that’s where he’s been hiding the bodies. It’s too dangerous to go near the place, so there’s no way of knowing how many people he’s murdered. Or how many more he’ll kill before he’s caught. As more horrors are discovered, ex-detective Ash Henderson is done playing nice. He’s got a killer to catch, and God help anyone who gets in his way. 

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 DI Rowan Jackman and DS Evans are told that the IT boss has disappeared, they soon suspect foul play. Orla Cracken, known as Orac, is no ordinary techie; she was once a field agent traveling abroad undercover, working for the government. Meanwhile DC Robbie Melton discovers that two people, both urban explorers, have mysteriously disappeared whilst out exploring abandoned buildings. One went missing at a disused airfield, but was it a military base, or was it civilian?

DI Nikki Galena gets a series of anonymous calls. She is told the place, time, and who will die. But the messages are in a secret language used only by villains. Nikki and her team must decode the riddles and work out where the threats are coming from.

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.