Mia has what many dream of: a real mermaid as her best friend! Molly lives just a pebble's throw away in the small bay, where the two of them dive for hidden treasures or swim with dolphins. But Molly has never been on land. Until the night of the Magic Moon, when all sea creatures can swim through the festively decorated streets as if by magic! How proud Mia is to show Molly her home for the first time and to swing high into the sky with her! But before the moon touches the sea, Molly has to be back in the sea, otherwise the magic will be gone forever. When Mia gets into trouble, the little mermaid has to make a decision