The sisters must face and destroy the demon that was responsible for their mother's death 20 years ago. In the process, they uncover a chapter of their mother's life that they never knew about - one that disturbingly mirrors Piper's current relationship with Leo.

Paige gets to know the Whitelighter in her, when she meets her first charge, a man named Sam, unbeknownst to her is actually her real father. Meanwhile Cole tries every possible way to get himself vanquished by the Charmed Ones. Piper and Leo have problems in finding a magical creature that does the babysitting part, and things go bad to worse when they're poisoned by a Darklighter, leaving Sam as the only one who can save them.

Wanting to return to her old career as a social worker, Paige's plans get put on hold, when her Whitelighter father, Sam, returns asking for her help with his charge. Meanwhile, Piper and Leo go to see a magical marriage counselor who thinks the best therapy is for them to walk a mile in each others' shoes - literally.