Owen Pick has just been suspended from his job as a teacher after accusations of sexual misconduct. Searching for professional advice online, he is inadvertently sucked into the dark world of incel forums, where he meets a charismatic and mysterious figure. Across the street from Owen lives the Fours family, headed by mom Cate, a physiotherapist, and dad Roan, a child psychologist. They think Owen is a bit creepy, and their teenaged daughter swears he followed her home from the train station one night. Meanwhile, young Saffyre Maddox spent three years as a patient of Roan Fours. Feeling abandoned when their therapy ends, she searches for other ways to maintain her connection with him. Then, on Valentine’s night, Saffyre disappears --- and the last person to see her alive is Owen Pick.

Shortly after her 25th birthday, Libby Jones returns home from work to find the letter she’s been waiting for her entire life. She soon learns not only the identity of her birth parents, but also that she is the sole inheritor of their abandoned mansion on the banks of the Thames, which is worth millions. But what she can’t possibly know is that others have been waiting for this day as well --- and she is on a collision course to meet them. Twenty-five years ago, police were called to 16 Cheyne Walk with reports of a baby crying. When they arrived, they found a healthy 10-month-old happily cooing in her crib in the bedroom. Downstairs in the kitchen lay three dead bodies, all dressed in black, next to a hastily scrawled note. And the four other children reported to live at Cheyne Walk were gone. But where?

You’re back home after four years working abroad, new husband in tow. You’re keen to find a place of your own. But for now, you’re crashing in your big brother’s spare room. That’s when you meet the man next door. He’s the head teacher at the local school. Twice your age. Extraordinarily attractive. You find yourself watching him. All the time. But you never dreamed that your innocent crush might become a deadly obsession. Or that someone is watching you.

As the headmaster credited with turning around the local school, Tom Fitzwilliam is beloved by one and all --- including Joey Mullen, his new neighbor, who quickly develops an intense infatuation with him. Joey thinks her crush is a secret, but Tom’s teenage son Freddie --- a prodigy with aspirations of becoming a spy for MI5 --- excels in observing people and has witnessed Joey behaving strangely around his father. One of Tom’s students, Jenna Tripp, also lives on the same street, and she’s not convinced that her teacher is as squeaky clean as he seems. Meanwhile, 20 years earlier, a schoolgirl writes in her diary, charting her doomed obsession with a handsome young English teacher named Mr. Fitzwilliam.

Laurel Mack is trying to put her life back together. It’s been 10 years since her daughter, Ellie, disappeared, seven years since her marriage ended, and only months since the last clue in Ellie’s case was unearthed. So when she meets an unexpectedly charming man in a café, no one is more surprised than Laurel at how quickly their flirtation develops into something deeper. Before she knows it, she’s meeting Floyd’s daughters --- and his youngest, Poppy, takes Laurel’s breath away. Because looking at Poppy is like looking at Ellie. And now, the unanswered questions about Ellie's disappearance that she has tried so hard to put to rest begin to haunt Laurel anew.

In a windswept British seaside town, single mom Alice Lake finds a man sitting on a beach outside her house. He has no name and no idea how he got there. Against her better judgment, she invites him inside. Meanwhile, newlywed Lily Monrose grows anxious when her husband fails to return home from work one night. Soon, she receives even worse news: the man she married never even existed. Twenty-three years earlier, Gray and Kirsty Ross are teenagers on a summer holiday with their parents. An enigmatic young man starts paying extra attention to Kirsty. Something about him makes Gray uncomfortable. Who is the man on the beach? Where is Lily’s missing husband? And what ever happened to the man who made such a lasting and disturbing impression on Gray?

Imagine that you live on a picturesque communal garden square, an oasis in urban London where your children run free, in and out of other people’s houses. You’ve known your neighbors for years, and you trust them. Implicitly. You think your children are safe. But are they really? On a midsummer night, as a festive neighborhood party is taking place, preteen Pip discovers her 13-year-old sister Grace lying unconscious and bloody in a hidden corner of a lush rose garden. What really happened to her? And who is responsible?

In the early hours of a summer morning, a young woman steps into the path of an oncoming bus. A tragic accident? Or suicide? At the center of this puzzle is Adrian Wolfe, a successful architect and grief-stricken widower, who, a year after his third wife’s death, begins to investigate the cause. As Adrian looks back on their brief but seemingly happy marriage, disturbing secrets begin to surface. Something, or someone, must have pushed Maya over the edge.