While Phoebe performs jury duty in a murder case, she is hit with a premonition about the real killer, and must convince the rest of the jury that the defendant is not guilty without exposing magic. Meanwhile, Piper, Paige and Leo try help Phoebe find the real murderer, but they stumble upon a gang of demons involved and they must solve the crime and keep Paige's friend out of danger before Phoebe gets thrown off the jury.

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 begins to go drastically wrong. Meanwhile, Phoebe attempts to divorce Cole, until he shows up claiming to want her back, Paige, attempts to juggle her new position as a full fledged Social Worker, as well as being a Charmed One, and Piper must protect her unborn baby, and face her fear of water.