Suzu is a 17-year-old high-school student living in a rural town with her father. Wounded by the loss of her mother at a young age, Suzu one day discovers the massive online world "U" and dives into this alternate reality as her avatar, Belle. Before long, all of U's eyes are fixed on Belle, when, suddenly, a mysterious, dragon-like figure appears before her.

A young girl is sent to the country for health reasons, where she meets an unlikely friend in the form of Marnie, a young girl with flowing blonde hair. As the friendship unravels it is possible that Marnie has closer ties to the protagonist than we might expect. Written by David On