A 4th grader raising her own daughter from 15 years in the future is the setup, but the real story is about a burnt-out aunt learning she matters more than her manga deadlines, one small disaster at a time. The show never rushes anything, a flooded kitchen, a missed school event, a quiet conversation about whether Natsumi will grow into the person Mirai needs her to be. It finds comedy in genuine exhaustion and warmth in the kind of family that accidentally builds itself.

On her first night alone after her parents leave for London, fourth-grader Natsumi Mizuki finds a baby who has appeared out of nowhere. The infant is Mirai, Natsumi's own daughter, who has somehow come back in time from fifteen years in the future. Now Natsumi must raise her while holding her school life together and keeping Mirai a secret from everyone. Her aunt Izumi, who has moved in to look after her, is chasing her first big break as a manga writer and offers only questionable help, though a few baby-care gadgets from the future make things a little easier. The show mixes comedy and drama with a light sci-fi premise.