Piper, Paige, and Leo struggle to convince Phoebe, now a mermaid, to come back to her life as a Charmed One, when she decides to swim away from her problems with Cole. Meanwhile, Piper casts a spell to stop her panic attacks but instead of facing her fear, she suppresses it, endangering herself and her baby, when a sea demon comes after Phoebe. In order to help Phoebe, Paige takes drastic measures and enlists the help of Cole. Later, Phoebe tells Cole that it is over between them and signs the divorce papers.