The first episode of "Bubble" introduces us to Arai Hibiki, a high school student who lives in Tokyo. Hibiki is a thrill-seeker who loves to take risks and live life on the edge. One day, while participating in a parkour session, he meets a mysterious girl named Uta, who seems to possess an unusual ability. As they spend more time together, Hibiki finds himself drawn to Uta's carefree and optimistic personality.