Peppermint Nanny, Hatoko Natsuyaki, known for her fondness of the unwanted peppermint candy drops of Fumi, undertook the upbringing of Fumi Koito. At present, Fumi has turned into a cram school teacher in his mid-20s and is living by himself. However, things take an unexpected turn when Hatoko, now a frail octogenarian, appears at Fumi's doorstep as a nine-year-old girl, following an excess of a magical youth-reviving elixir. Despite her age, Hatoko still wishes to cook and care for Fumi, and they both embark on an uncertain journey together, where it's hard to distinguish between the caregiver and the one being cared for.
