Seven years ago, Kate Hartfield's little sister disappeared.

An ordinary summer day of fun at the lake turned into a nightmare when young Emily Hartfield suddenly could not be found. When badly battered body parts were discovered three days later, the investigation concluded that they were Emily's and the case was closed as an accidental drowning.

Now Kate has returned to her hometown in the Catskills for the first time since her sister's death, for a work retreat. While at her boss's lake house, she briefly spies a familiar face.

It's Emily.

She's all grown up, but Kate knows her sister's face better than anyone. The sighting reignites the doubts Kate has always had, and forces her to revisit all the mysterious circumstances that surrounded that day. As she desperately tries to track down the girl she saw at the lake house with the help of her hometown ex-boyfriend, Kate discovers shocking secrets from the past, confronts her own guilt from that day, and becomes obsessed with uncovering the answer to one question.

What really happened to Emily?