Jinta Yadomi is living as a recluse, skipping high school and passing days with video games, until the ghost of his childhood friend, Meiko "Menma" Honma, appears before him. Menma died in a tragic accident five years prior, which caused their tight-knit group of friends—the "Super Peace Busters"—to drift apart. Menma returns as a spirit that only Jinta can see, claiming she has a wish that must be granted before she can move on. To fulfill her request, Jinta must reunite his estranged friends, forcing each of them to confront their long-buried guilt, shared trauma, and the complex feelings that have haunted them since the day of the accident.