What if your new friend is a mermaid, and nobody else can see her? Maia is going to the race, but it's early. She stops to look at her reflection in the pond. The reflection turns into another girl -- a girl who is swimming -- a girl who is a mermaid named Trezzie. Trezzie takes Maia's hand and together they swim to her castle under the water. She gives Maia a piece of a plant that becomes a doorbell, so Maia can call her any...