A shy high schooler in Kyoto meets a man claiming to be his future self, who tells him he’s hacked into the past to save their first love.

Mermaids are known worldwide as bewitching mythological creatures of the sea. Despite their charms and otherworldly powers, daily life for these beings comes with everyday problems. But there’s nothing that can’t be overcome with the support of friends. Follow the adventures of five young mermaids as they explore their town and the world around them in this delightful slice-of-life series that takes viewers to an enchanting world beneath the waves.

"If you blush, you lose." Living by this principle, the middle schooler Nishikata gets constantly made fun of by his seat neighbor Takagi-san. With his pride shattered to pieces, he vows to turn the tables and get back at her some day. And so, he attempts to tease her day after day, only to find himself victim to Takagi-san's ridicule again sooner than later. Will he be able to make Takagi-san blush from embarrassment even once in the end?