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…

Piper, Phoebe and Paige come to the aid of Mylie, a Mermaid-turned-human, when she shows up looking for their help after a pact she made with an evil Sea Hag…