Sirena, Nixie and Lyla are part of a mermaid pod, which lives in the waters of Mako Island. As young members of the pod, it is their job to protect the Moon Pool ... a pod of mermaids call home.

Curious about where to watch Mako ... of the powerful moon pool. Meanwhile, a dark secret threatens to surface, putting the mermaids’ identities and the entire island at risk.

The chamber's true purpose is revealed: to drain the magic from all mermaids. Zac risks his life to shut it down and restore the mermaids' magic.