After saving Ayame from drowning, Kou developed feelings for her and affectionately calls her a mermaid. However, Ayame is enamored with Kou's elder brother, who is also the advisor for their school's swimming club – much to Kou's disappointment.
Kou is willing to go to lengths for Ayame's love and believes her efforts to win over his brother are naive. Despite this, Ayame persists and hopes he will someday acknowledge her feelings. It begs the question, can Kou ever return Ayame's favor and show her the same level of love?
