This is the second series.
Sara had forgiven Tarō Mitsuki for the mistakes he made in the past (her hate for him disappeared and her black hair reverted to its orange color). But since she became such a close friend to Gaito and she wanted to share his fate for everything he has done, she decided to entrust her orange pearl to Lucia and join Gaito in his demise. The Marine World may go back to normal, but it has one less Mermaid Princess.
Enter Seira, the new owner of the orange pearl. But she's not born yet; just a spirit who appears to Lucia in her dreams. In order for Seira to be born, her heart (心, kokoro) must merge with the orange pearl. But even before this happens, her heart is stolen by an angel named Mikeru. Lucia (together with Hanon and Rina) must retrieve pieces of her heart, even if she will face an almost unbeatable foe.
On the other hand, Kaito and Lucia love each other more, especially that Kaito has finally figured out that she is the mermaid who rescued him seven years before. But they are about to be separated once again when Kaito bounds for Hawaii to continue searching for the truth about his identity. But while in Hawaii, a surfing accident erases all of his memories. He is found and tended by a girl named Mikaru who has feelings for him. Lucia has to cope with this shock and attempt to let him remember at least some of his memories, especially of her.
Along with Lucia's romantic troubles, this season also highlights Hanon and Rina's love stories. Hanon rejects a persistent suitor, but finds newfound love with him after her fixation with her music teacher, Tarō Mitsuki, ends in disappointment. The story also covers Rina's first experience of love...
Many new villains and villainesses appear, including the return of some older characters. This season also features songs for the villains as well as newer ones for the mermaids.
an extended description!