Rize Amami is a descendant of a mermaid bloodline and carries a jewel infused with mermaid power. On her fourteenth birthday, she undergoes her first transformation into a mermaid, but her classmate Ruka Kanda, a notorious troublemaker, witnesses the event. Rather than exposing her secret, Ruka becomes fixated on obtaining her mermaid tears, which are said to be able to cure any illness or ailment. He begins relentlessly pursuing Rize, tormenting her in an attempt to make her cry and harvest the legendary tears. The story follows Rize as she navigates the dangers of her hidden heritage and Ruka's obsessive quest, set against the backdrop of their everyday school life. As the two clash, the boundaries between tormentor and protector blur, revealing deeper layers to Ruka’s motives and the true nature of the mermaid curse. Serialized in Shogakukan's shoujo magazine, the manga is illustrated by Asuka Ogura and blends fantasy elements with a sentimental tone, exploring themes of immortality, sacrifice, and the price of a miracle cure. The narrative unfolds across escalating encounters where Rize must decide whether Ruka is her greatest threat or her only ally.