High school girl Kako Kousaka is living a quiet, ordinary life until a pink-haired stranger named Mirai shows up at her door carrying a baby. Mirai immediately announces that the baby, Nozomi, is Kako’s child—conceived between Kako and Mirai somewhere in the future. Mirai herself is a time traveler from that future, and she has come to the present to live with Kako, insisting on acting as her self-proclaimed wife. Kako has no memory of any such relationship and is completely bewildered, but Mirai and Nozomi refuse to leave, forcing her into an unexpected domestic arrangement.

The story follows the chaotic daily life of this makeshift family. Kako must juggle her responsibilities as a high school student with suddenly having to care for a baby alongside a mysterious woman who claims to be her future partner. Mirai is energetic, confident, and often oblivious to social norms, while Kako is more reserved and practical, leading to constant comedic friction. Nozomi, the baby, is a catalyst for bonding and confusion alike. As they live together, Kako gradually warms to the situation, and hints of genuine romantic and familial feelings begin to develop. The narrative balances slapstick humor with tender moments of childcare, and threads of time‑travel mystery—such as why Mirai really came to the past and what future events led to Nozomi’s existence—are woven through the everyday comedy.

The manga is set primarily in Kako’s apartment and her school, with occasional excursions that highlight the absurdity of Mirai’s futurisms. Notable arcs include early misunderstandings and attempts to hide the situation from friends, learning to care for Nozomi together, small glimpses of the future through Mirai’s knowledge, and deepening emotional intimacy between the two girls. The tone remains lighthearted and affectionate, emphasizing found family and the unexpected paths love can take.