When Char Hawthorne's husband dies unexpectedly, she is left questioning everything she once knew to be true: from the cozy small town life they built together to her relationship with her stepdaughter, who is suddenly not bound to Char in any real way. Untethered explores what bonds truly form a family and how, sometimes, love knows no bounds.

Char Hawthorn, college professor, wife and stepmother to a spirited fifteen-year-old daughter, loves her family and the joyful rhythms of work and parenting. But when her husband dies in a car accident, the "step" in Char's title suddenly matters a great deal. In the eyes of the law, all rights to daughter Allie belong to Lindy, Allie's self-absorbed biological mother, who wants to girl to move to her home in California.

While Allie begins to struggle in school and tensions mount between her and Char, Allie's connection to young Morgan, a ten-year-old-girl she tutors, seems to keep her grounded. But then Morgan, who was adopted out of foster care, suddenly disappears, and Char is left to wonder about a possible future without Allie and what to do about Morgan, a child caught up in a terrible crack in the system.