Twenty years after her twin sister's disappearance, Tess Piper is forced to confront her family's dark past when a body is discovered, implicating her own family in the crime. Tess has spent two decades building a life away from the trauma of her sister Edie's vanishing, but the discovery of a body and the subsequent police investigation into her family shatter her carefully constructed peace. The narrative explores the suffocating weight of unresolved grief and the secrets that fester within families, as Tess must navigate the suspicion cast upon her loved ones and uncover the truth about what happened to Edie, knowing that the perpetrator is likely someone they trusted.

The reader reviews indicate that 'Someone You Know' is a highly engaging and suspenseful thriller that successfully keeps readers guessing. Many reviewers praised the book's ability to maintain intrigue until the very end, with some admitting they could not predict the 'baddie'. The narrative is described as dark, twisted, and atmospheric, with a strong focus on familial secrets and sibling dynamics. The book is frequently recommended for fans of mystery, murder, and unexpected plot twists, with multiple comments highlighting its unputdownable nature and satisfying, killer ending.