Pay close attention, and you might solve this. On Monday afternoon five students at Bayview High walk into detention. Bronwyn, the brain, is Yale-bound and never breaks a rule. Addy, the beauty, is the picture-perfect homecoming princess. Nate, the criminal, is already on probation for dealing. Cooper, the athlete, is the all-star baseball pitcher. And Simon, the outcast, is the creator of Bayview High's notorious gossip app. Only Simon never makes it out of that classroom. Before the end of detention, Simon's dead.

Echo Ridge is small-town America. Ellery's never been there, but she's heard all about it. Her aunt went missing there at age 17. And only five years ago, a homecoming queen put the town on the map when she was killed. Now, Ellery has to move there to live with a grandmother she barely knows. The town is picture-perfect, but it's hiding secrets. And before school even begins for Ellery, someone has declared open season on homecoming, promising to make it as dangerous as it was five years ago. Then, almost as if to prove it, another girl goes missing.

Pretty and popular high school senior Andie Bell was murdered by her boyfriend, Sal Singh, who then killed himself. It was all anyone could talk about. And five years later, Pip sees how the tragedy still haunts her town. But she can't shake the feeling that there was more to what happened that day. She knew Sal when she was a child, and he was always so kind to her. How could he possibly have been a killer?

Kay Donovan has skeletons in her closet, but who doesn't? The past is the past, and now Kay's a star soccer player whose group of gorgeous, pedigreed friends run their private school with effortless popularity and acerbic wit. But when a girl's body is found in the lake, Kay's carefully constructed life begins to topple. The dead girl has left a memento, a computer-coded scavenger hunt, which, as it unravels, begins to implicate each of Kay's friends, until Kay herself is in the crosshairs of the murder investigation.

There are no more cheerleaders in the town of Sunnybrook. First there was the car accident - two girls dead after hitting a tree on a rainy night. Not long after, the murders happened. Those two girls were killed by the man next door. The police shot him, so no one will ever know his reasons. Monica's sister was the last cheerleader to die. After her suicide, Sunnybrook High disbanded the cheer squad. No one wanted to be reminded of the girls they'd lost.

Kacey is the new girl in Broken Falls. When she moved in with her father, she stepped into a brand-new life. A life with a stepbrother, a stepmother, and, strangest of all, an adoring younger half sister. Kacey's new life is eerily charming compared with the wild highs and lows of the old one she lived with her volatile mother. And everyone is so nice in Broken Falls - she's even been welcomed into a tight new circle of friends. Bailey and Jade invite her to do everything with them.

On an island off the coast of Ireland, guests gather to celebrate two people joining their lives together as one. The groom: handsome and charming, a rising television star. The bride: smart and ambitious, a magazine publisher. It’s a wedding for a magazine or for a celebrity: the designer dress, the remote location, the luxe party favors, the boutique whiskey. The cell phone service may be spotty and the waves may be rough, but every detail has been expertly planned and will be expertly executed.

Years ago, bookseller and mystery aficionado Malcolm Kershaw compiled a list of the genre’s most unsolvable murders, those that are almost impossible to crack - which he titled "Eight Perfect Murders". But no one is more surprised than Mal, now the owner of the Old Devils Bookstore in Boston, when an FBI agent comes knocking on his door one snowy day in February. She’s looking for information about a series of unsolved murders that look eerily similar to the killings on Mal’s old list. And the FBI agent isn’t the only one interested in this bookseller.

Ellingham Academy is a famous private school in Vermont for the brightest thinkers, inventors, and artists. It was founded by Albert Ellingham, an early 20th century tycoon, who wanted to make a wonderful place full of riddles, twisting pathways, and gardens. "A place", he said, "where learning is a game." Shortly after the school opened, his wife and daughter were kidnapped. The only real clue was a mocking riddle listing methods of murder, signed with the frightening pseudonym "Truly, Devious".

Sadie hasn't had an easy life. Growing up on her own, she's been raising her sister, Mattie, in an isolated small town, trying her best to provide a normal life and keep their heads above water. But when Mattie is found dead, Sadie's entire world crumbles. After a somewhat botched police investigation, Sadie is determined to bring her sister's killer to justice and hits the road following a few meager clues to find him. When West McCray - a radio personality working on a segment about forgotten towns in America - overhears Sadie's story, he becomes obsessed with finding the girl.

Milly, Aubrey, and Jonah Story are cousins, but they barely know each another, and they've never even met their grandmother. Rich and reclusive, she disinherited their parents before they were born. So when they each receive a letter inviting them to work at her island resort for the summer, they're surprised...and curious. Their parents are all clear on one point - not going is not an option. This could be the opportunity to get back into Grandmother's good graces. But when the cousins arrive on the island, it's immediately clear that she has different plans for them.

Ellingham Academy must be cursed. Three people are now dead. One, a victim of either a prank gone wrong or a murder. Another, dead by misadventure. And now, an accident in Burlington has claimed another life. All three in the wrong place at the wrong time. All at the exact moment of Stevie's greatest triumph.... She knows who Truly Devious is. She's solved it. The greatest case of the century.

Stephanie and Patrick are adjusting to life with their colicky twin girls. The babies are a handful, but even as Stephanie struggles with the disorientation of sleep deprivation, there's one thing she's sure of: She has all she ever wanted. Then Erica, a woman from Patrick's past, appears and makes a disturbing accusation. Patrick had always said his first wife's death was an accident, but now Erica claims it was murder. Patrick insists he's innocent, that this is nothing but a blackmail attempt. Still, Erica knows things about Patrick.

When Anna Cicconi arrives to the small Hamptons village of Herron Mills for a summer nanny gig, she has high hopes for a fresh start. What she finds instead is a community on edge after the disappearance of Zoe Spanos, a local girl who has been missing since New Year’s Eve. Anna bears an eerie resemblance to Zoe, and her mere presence in town stirs up still-raw feelings about the unsolved case. As Anna delves deeper into the mystery, stepping further and further into Zoe’s life, she becomes increasingly convinced that she and Zoe are connected.

10:00 a.m. The principal of Opportunity, Alabama's high school finishes her speech, welcoming the entire student body to a new semester and encouraging them to excel and achieve. 10:02 a.m. The students get up to leave the auditorium for their next class. 10:03. The auditorium doors won't open. 10:05. Someone starts shooting. Told over the span of 54 harrowing minutes from four different perspectives, terror reigns as one student's calculated revenge turns into the ultimate game of survival.