Two couple are involved in an unfortunate baby switch, and the doctors must handle and solve it. Sam treats a client that may upset Naomi. A grandmother goes to extreme lengths to stop her son killing himself with alcohol, but her plan backfires.

In this Addison-centric episode, her role as a parent is challenged when Henry's biological mother reappears and asks to be more involved in her young son's life. Meanwhile Addison reconnects with her mentor, who shares a very painful secret.

Charlotte continues to run the hospital from her bed; Mason starts acting out in school.