In the latest jaw-dropping thriller from New York Times bestselling author Riley Sager, a man must contend with the long-ago disappearance of his childhood best friend—and the dark secrets lurking just beyond the safe confines of his picture-perfect neighborhood. The worst thing to ever happen on Hemlock Circle occurred in Ethan Marsh’s backyard. One July night, ten-year-old Ethan and his best friend and neighbor, Billy, fell asleep in a tent set up on a manicured lawn in a quiet, quaint New Jersey cul-de-sac. In the morning, Ethan woke up alone. During the night, someone had sliced the tent open with a knife and taken Billy. He was never seen again. Thirty years later, Ethan has reluctantly returned to his childhood home. Plagued by bad dreams and insomnia, he begins to notice strange things happening in the middle of the night. Someone seems to be roaming the cul-de-sac at odd hours, and signs of Billy’s presence keep appearing in Ethan’s backyard. Is someone playing a cruel prank? Or has Billy, long thought to be dead, somehow returned to Hemlock Circle? The mysterious occurrences prompt Ethan to investigate what really happened that night, a quest that reunites him with former friends and neighbors and leads him into the woods that surround Hemlock Circle. Woods where Billy claimed ghosts roamed and where a mysterious institute does clandestine research on a crumbling estate. The closer Ethan gets to the truth, the more he realizes that no place—be it quiet forest or suburban street—is completely safe. And that the past has a way of haunting the present.

Sixteen-year-old Denny lives in the shadow of a deadly accident with which his father was connected when he was Denny's age, a disaster for which some of the survivors still blame his father.