You are a normal high school student who has a crush on a cute classmate, Isla. Knowing that she likes a guy who swims well, you decide to teach yourself at the beach to impress her. But you are caught in the waves and get dragged under. Just as you think you’re done for; someone appears and saves you. As you open your eyes, you find out there are three girls arguing-Isla and another two girls. The two girls are clearly aren’t human; they have Killer Whale tail and jellyfish-like hat in their body. Surprised, you try to run away but Isla comes after you. But in the process, you both fall into the water and you see Isla turn into a mermaid! “We are going to watch you… not to disclose our secret!” Your normal life starts to roll dynamically with Isla’s sudden kiss…Now, can you imagine how will your story end like with these unique girls?