In this beautifully written novel that blends the whimsy of The Time Traveler's Wife with an indelible portrait of motherhood, a young woman strives to pick up the pieces after her husband mysteriously leaves—and she finds strength from the unlikeliest of allies.

Jenny Lipkin is an average, stretched-too-thin Brooklyn mom tackling the challenges of raising two children in a cramped Park Slope walk-up and bonding with the other moms about breast-feeding while spending endless hours in Prospect Park. All she really wants is to survive the sweltering New York summer with a shred of sanity intact. But when her husband Harry, a compulsive gambler, vanishes one evening without a word, Jenny finally reaches her breaking point. In a moment of despair, a split-second decision changes her life forever.

Pulled from the brink by an unexpected—and as it turns out, sometimes annoying—supernatural ally, Jenny is forced to rethink her ideas about success, motherhood, romance, and relationships. Confronting her inner demons—of both the mermaid and nonmermaid variety—is no easy task, and eventually Jenny has to come to terms with who she truly is, for better or worse.