Description：For a long time, Ryuji (voiced by Shimazaki Nobunaga) has lived a life alone. On the surface, Ryuji has a cold and unkind personality, but in fact, he is very good at housework and has a soft heart. From one day on, Ryuji was no longer alone, and the extra "companion" turned out to be the mermaid Wakasa (voiced by Umehara Yuichiro) who lived in his bathtub. The pessimistic and short-sighted Shell Maki (voiced by Tsuda Kenjiro), the uninvited jellyfish Sangoku (voiced by Hanae Natsuki), the clever octopus Eagle Nest (voiced by Suzuki Tatsuhisa), and the two-faced shark Anheli, since Ryuji appeared, these strange marine creatures have also begun to appear one after another in Ryuji's life. In the process, the relationship between Ryuji and Wakasa seems to become closer and closer.