They are elites trained by the Fish Hunter School. In order to protect a seaside town from being slaughtered by mermaids, one of the three elites turned out to be a mermaid. He sneaked into the Fish Hunter School, learned skills, and stole intelligence. For the mermaid family, he, she and Lan Ting The residents of the town turned against each other, leading to a bloody storm ten years ago. They met again ten years later and fell in love with each other after losing their memories. When the truth of ten years ago emerged, she would follow him around the world, or use his blood to commemorate the town she loved.