Karen Sherburne is a hardworking single mom and social worker. Hoping to make more time for her daughter, Meg, she commits to cutting back on her fifty-hour workweek. Not long after this decision, Meg is murdered-and no suspect can be found. In her grief, Karen becomes obsessed with one goal: find the killer; kill the killer.
When she returns to work, Karen is assigned a new case: fifteen-year-old Frankie Ortiz, an abuse victim. Through adoption, Karen hopes to save Frankie as she could not save her own daughter.
Meanwhile, Kendra Bruno uses witchcraft in an attempt to discover the parents who abandoned her. Instead of finding her parents, a figure appears in Kendra's bedroom mirror: a figure belonging to the ghost of Karen's daughter, Meg.
As the lives of Karen, Frankie, and Kendra intersect, secrets are revealed from an unforeseen source. Meg has a message-not only for her mother-but for Kendra, too-and Karen might be the only person who can save Frankie from a horrific fate. When Karen finally discovers her daughter's killer, will she be able to stick to her vow of vengeance, or will her newfound relationships shake her resolve?