Plot
Mermaid princess Lucia Nanami has survived several villainous attacks, that also threaten her fellow princesses, her relationship with her beloved, Kaito, and the health of the seven seas! When the evil Gackto captures one of Lucia’s allies, she has no choice but to gather a rescue party and head to the deepest part of the ocean to confront her enemy. But in the deep-sea castle that is Gackto’s fortress home, the magic of the princesses’ pearls won’t work. How can a girl survive in the enemy’s lair with no more powers than those of a normal teenager?