Written in the cadences, if not the actual language, of water, Johnson’s shimmering first novel unfolds along a river. The narrative borrows from fairy tale and myth, telling a story in which everything is fluid and shifting, from relationships and identities to gender, language, and reality itself. This is a realm where conventions come unstuck, where a mysterious creature called the Bonak lurks, and where things and people are easily lost. Much of the action focuses on Gretel’s efforts to find Sarah, her mother, who went missing sixteen years before; now suffering from Alzheimer’s, as well as still harboring a number of secrets, Sarah remains elusive even when present. But Gretel, a lexicographer, is used to delving into the past (though often with ambiguous outcomes—the Bonak “might never have been there if we hadn’t thought it up,” she says). As her story widens to include those of others lost and found, Johnson spins an ever richer tale that meditates on ancient questions of fate vs free will as well as contemporary questions of family and sexuality.