As Lucia plans to light a candle with Kaito's name on it, she also experiences conflicting emotions when she realizes Kaito still hasn't yet discovered she is his precious mermaid.When Lucia hears a rumor that Kaito is dating an older girl, she sets out to investigate.Despite this, during a festival later, Hanon, too, finds love. Hanon's mermaid form is also revealed as the South Atlantic Mermaid Princess.Hanon finds out that the handsome man she met at the festival is her music teacher, Taro Mitsuki.Taro has been reassigned as Lucia, Hanon, and Rina's homeroom teacher.Elated, Hanon organizes an outdoor welcome party for him.They also find out about a tune their teacher wrote for the mermaid he met during a trip in India. Kaito and his friends are throwing Lucia a birthday party at a beach house.
In the end, the spirits of the two lovers possess Kaito and Lucia's bodies to share a kiss before rising to the afterlife.
It chronicles the basic premise mentioned above and adapts stories from the first twenty chapters of the manga. She finds him, Kaito Domoto, but does not know it is him until later.