After the final battle against Gaito, Sara sacrifices her life to remain with him. With the sea world now at peace, only six mermaid princesses protect it. While Caren, Noel, and Coco have returned to their kingdoms, it is time for Lucia, Hanon, and Rina to do the same. Mitsuki Tarou is leaving for Germany and Doumoto Kaito is heading to Hawaii. Lucia is devastated, and when things couldn’t get any worse, Kaito is lost at sea. To make matters worse, a strange angel named Michel appears, urging the mermaids to join him. On a brighter note, Sara’s spirit tells Lucia of her successor, a young mermaid named Seira. The mermaids are in for another adventure.