Melville Heights is one of the nicest neighborhoods in Bristol, England; home to doctors and lawyers and old-money academics. It’s not the sort of place where people are brutally murdered in their own kitchens. But it is the sort of place where everyone has a secret. And everyone 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 this thoroughly charming yet unavailable man. Joey thinks her crush is a secret, but Tom’s teenaged 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 her teacher is as squeaky clean as he seems. For one thing, he has taken a particular liking to her best friend and fellow classmate, and Jenna’s mother—whose mental health has admittedly been deteriorating in recent years—is convinced that Mr. Fitzwilliam is stalking her.

Meanwhile, twenty years earlier, a schoolgirl writes in her diary, charting her doomed obsession with a handsome young English teacher named Mr. Fitzwilliam…