Hotori is a high school student with one month left to live. Two shinigami—Zen and Rikka—are sent down to watch over her for that month, ensuring she has no regrets before she passes into the afterlife. If they succeed, they earn the right to be reborn. If they fail, they are bound to shinigami duties for eternity. Hotori, unaware of this arrangement, spends her remaining time thinking about how to live fully—and at the top of that list is confessing her feelings to her crush, Shizuru.