Japan, after suffering from a massive irreparable disaster, cuts itself off from the world. Children are so weak they can barely stand or walk: the only people with any get-go are the elderly. Mumei lives with his grandfather Yoshiro, who worries about him constantly. They carry on a day-to-day routine in what could be viewed as a post-Fukushima time, with all the children born ancient -- frail and gray-haired, yet incredibly compassionate and wise. Mumei may be enfeebled and feverish, but he is a beacon of hope, full of wit and free of self-pity and pessimism.