An eclectic group of college friends, eager to push the limits, call themselves ‘The Compassionate Dismantlers’ because they believe to truly understand something—or someone—you have to literally take it apart, breaking it down to see the basic pieces. Henry, Tess, Spencer, Winnie and Suz spend the summer after graduation together in a remote Vermont cabin wreaking havoc on local businesses and plotting elaborate and sometimes dangerous pranks. When one project spirals horrifically out of control and culminates in Suz’s death, the group tries to cover it up and forget the tragic summer all together. Nearly a decade later, one of the members commits suicide unable to let go of what happened that fateful summer, setting off a chain of eerie events that brings that catastrophic summer rushing to the present.

Forty-one-year-old school nurse Kate Cypher has returned home to rural Vermont to care for her mother who's afflicted with Alzheimer's. On the night she arrives, a young girl is murdered--a horrific crime that eerily mirrors another from Kate's childhood. Three decades earlier, her dirt-poor friend Del--shunned and derided by classmates as "Potato Girl"--was brutally slain. Del's killer was never found, while the victim has since achieved immortality in local legends and ghost stories. Now, as this new murder investigation draws Kate irresistibly in, her past and present collide in terrifying, unexpected ways. Because nothing is quite what it seems . . . and the grim specters of her youth are far from forgotten. More than just a murder mystery, Jennifer McMahon's extraordinary debut novel, "Promise Not to Tell," is a story of friendship and family, devotion and betrayal--tautly written, deeply insightful, beautifully evocative, and utterly unforgettable.