From the hugely talented author of The Kind Worth Killing comes an exquisitely chilling tale of a young suburban wife with a history of psychological instability whose fears about her new neighbor could lead them both to murder. . . .

Hen and her husband, Lloyd, have settled into a quiet life in a suburban house outside of Boston. Hen (short for Henrietta) is an illustrator and has set up shop in a nearby studio, where she can forget the world and focus on her craft. After a few exhausting years of trial and error she has found the right meds to control her bipolar disorder. Finally, she’s found some stability and peace to do what she loves—create.

But when they meet the couple next door, that calm begins to erode when she spots a familiar object in the husband’s office. It looks exactly like something connected to a killing that happened years ago—one of very few pieces of evidence in a disturbing and baffling case. Hen recognizes it instantly because she’s long had a fascination with this unsolved murder—an obsession she doesn’t talk about anymore, but can’t fully shake either.

Could her neighbor Matthew be a killer? Or is this the beginning of another psychotic episode like the one she suffered in college, when she became so consumed with a friend’s guilt that she ended up hurting someone? The more Hen observes Matthew, the more she suspects he’s planning something truly terrifying. Yet no one will believe her. Then one night, when she comes face-to-face with Matthew in the dark, she realizes that he knows she’s been watching him, that she really is on to him. And that this is the start of a horrifying nightmare she may not live to escape. . . .