In Pamplona, capital of Navarra, Amaia Salazar is called in to investigate the death of a baby girl. The baby has red marks on her face, indicating she has been murdered. According to the girl's grandmother, the father tried to run away with the body, uttering something about an offering. She also mentions the Inguma - an evil being of Basque mythology that kills people in their sleep. The investigation takes Amaia and her team to the nearby valley of Baztan, where there have been an abnormally high number of similar cases - and some procedural irregularities.

Amaia Salazar, a young detective from the north of Spain, has joined a group of trainees at the FBI Academy in Virginia. Haunted by her past and having already tracked down a predator on her own, Amaia is no typical rookie. And this is no ordinary student lecture at Quantico. FBI agent Aloisius Dupree is already well acquainted with Amaia’s skills, her intuition, and her ability to understand evil. He now needs her help in hunting an elusive serial killer dubbed “the Composer,” and in solving another case that’s been following him his whole life.

When novelist Manuel Ortigosa learns that his husband, Álvaro, has been killed in a car crash, it comes as a devastating shock. It won’t be the last. He’s now arrived in Galicia. It’s where Álvaro died. It’s where the case has already been quickly closed as a tragic accident. It’s also where Álvaro hid his secrets. The man to whom Manuel was married for fifteen years was not the unassuming man he knew.

The year is 1896, the place, New York City. On a cold March night New York Times reporter John Schuyler Moore is summoned to the East River by his friend and former Harvard classmate Dr. Laszlo Kreizler, a psychologist, or "alienist." On the unfinished Williamsburg Bridge, they view the horribly mutilated body of an adolescent boy, a prostitute from one of Manhattan's infamous brothels.

Clare Cassidy is no stranger to murder. A high school English teacher specializing in the Gothic writer R. M. Holland, she teaches a course on it every year. But when one of Clare’s colleagues and closest friends is found dead, with a line from R. M. Holland’s most famous story, “The Stranger”, left by her body, Clare is horrified to see her life collide with the story lines of her favorite literature. 

At an internment camp in Indonesia, 47 people are pronounced dead with acute hemorrhagic fever. When Henry Parsons - microbiologist, epidemiologist - travels there on behalf of the World Health Organization to investigate, what he finds will soon have staggering repercussions across the globe: an infected man is on his way to join the millions of worshippers in the annual Hajj to Mecca. Now, Henry joins forces with a Saudi prince and doctor in an attempt to quarantine the entire host of pilgrims in the holy city.... 

The year is 1924. Only a few years removed from the trenches of Flanders, Lieutenant Eric Peterkin has just been granted membership in the most prestigious soldiers-only club in London: the Britannia. But when a gentleman's wager ends with a member stabbed to death, the victim's last words echo in the lieutenant's head: that he would "Soon right a great wrong from the past".  Eric is certain one of his fellow members is the murderer. But who?

When 10-year-old cousins Maddy and Brianna are arrested for a terrible crime, Maddy’s mother, Juliet, cannot believe it. How could her bright, joyful daughter be capable of such a thing? As the small village community recoils in horror, the pressure of the tragedy blows Juliet and her sister’s lives apart. And things get even worse when their daughters retreat into a self-imposed silence. Can anyone reach Maddy and discover the truth before her fate is sealed? Juliet is crushed. Nothing will ever be the same for her darling girl.

Coming from scandalous Florida treasure hunters and drug smugglers, Sloan McPherson is forging her own path, for herself and for her daughter, out from under her family’s shadow. An auxiliary officer for Lauderdale Shores PD, she’s the go-to diver for evidence recovery. Then Sloan finds a fresh kill floating in a canal - a woman whose murky history collides with Sloan’s. Their troubling ties are making Sloan less a potential witness than a suspect. And her colleagues aren’t the only ones following every move she makes. So is the killer.

After finding himself caught up in one of Louisiana’s oldest and bloodiest family rivalries, Detective Dave Robicheaux must battle the most terrifying adversary he has ever encountered: a time-traveling superhuman assassin.

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.

Will Burgess is used to hard knocks. Abandoned by his father, son of a drug-addicted mother, and charged with raising his six-year-old sister, Will has far more to worry about than most high school freshmen. To make matters worse, Mia Samuels, the girl of Will’s dreams, is dating his worst enemy, the most sadistic upperclassman at Shadeland High. Will’s troubles, however, are just beginning. Because one of the nation’s most notorious criminals - the Moonlight Killer - has escaped from prison and is headed straight toward Will’s hometown.

Kate Rees, a young American markswoman, has been recruited by British intelligence to drop into Paris with a dangerous assignment: assassinate the Fuhrer. Wrecked by grief after a Luftwaffe bombing killed her husband and infant daughter, she is armed with a rifle, a vendetta, and a fierce resolve. But other than rushed and rudimentary instruction, she has no formal spy training. Thrust into the red-hot center of the war, a country girl from rural Oregon finds herself holding the fate of the world in her hands.

Along the ever-changing border of gentrifying Los Angeles, 17-year-old Monique Darson is found dead at a condominium construction site, hanging in the closet of an unfinished unit. Homicide Detective Elouise "Lou" Norton's new partner, Colin Taggert, fresh from the comparatively bucolic Colorado Springs police department, assumes it's a teenage suicide. Lou isn't buying the easy explanation. For one thing, the condo site is owned by Napoleon Crase, a self-made millionaire...and the man who may have murdered Lou's missing sister, Tori, 30 years ago. 

The only person who might have the answers to a baffling murder case is the victim's seven-year-old daughter, found hiding in the room where her mother died. And she's not talking. Newly-promoted, out of his depth, detective Huldar turns to Freyja for her expertise with traumatized young people. Freyja, who distrusts the police in general and Huldar in particular, isn't best pleased. But she's determined to keep little Margret safe. It may prove tricky. The killer is leaving them strange clues: warnings in text messages, sums scribbled on bits of paper, numbers on the radio.