The Lying Game, by Ruth Ware

More a suspense novel than a mystery, this 2017 novel from Ruth Ware starts with a body turning up by a tidal estuary on the south coast of England. The next day Isa Wilde, living in North London with her husband and six-month-old daughter, receives a text saying simply “I need you.”

To her husband’s baffled dismay, Isa immediately packs up her baby and leaves for the village of Saltern, where 17 years earlier she had briefly attended a boarding school. There she’d become tight friends with...