Widowed mommy-blogger Stephanie Ward receives a call from her best friend, Emily Nelson, asking her to pick up Emily's five-year-old son, Nicky, from school. There's an emergency at work, Emily explains, but she'll be by to get Nicky no later than 9 p.m. Nicky is best friends with Stephanie's son, Miles, and the boys attend the same suburban Connecticut kindergarten, so Stephanie agrees. Days pass and Emily never appears, leading Stephanie to fear the worst. Emily's husband, Sean, returns home from his European business trip and calls the police, who assume that Emily has simply run away -- until her body washes up at her family's lake house in Michigan. Stephanie initially seeks to comfort Sean, but when questions arise surrounding Emily's death, she's left wondering what is true and whom to trust.