Suzu, a seventeen-year-old high school student living in rural Kochi Prefecture, has kept the world at arm's length ever since her mother's death years ago. But at a friend's urging, she decides to dip her toes into another world: U, the largest online community in history. As her avatar, Belle, Suzu reveals her hidden singing talent and instantly becomes a global internet sensation, leading her to cross paths with a mysterious beast known as the Dragon. Who is this ferocious yet lonely stranger, and what will come of their fateful encounter...?