How well do you know your friends?

Isolated and embroiled in a custody battle, Mary is desperate for a friend. So when she meets the charming and enigmatic Willa at a Brooklyn playground, their connection feels fated. But during a margarita-fueled moms' night out, Mary shares her darkest secret about her ex, George, and the next morning Willa simply disappears. No calls, no texts, nothing.

Two months later, Mary's divorce is almost finalized, and she's trying to build a new life for her son in upstate New York. On her first day in town, she runs into Willa . . . only Willa's name is now Annie, and she's got an entirely new family in tow. When George turns up dead and Mary becomes the prime suspect, she has no choice but to turn to her only friend in town: Willa.

As coincidences-and evidence-pile up, Mary begins to wonder whether Willa had something to do with George's death. Is the woman a friend or a foe, a confidante or just a con? Mary must uncover the truth before she loses everything.