Shōko Nogami, a young woman readjusting to life in Japan after years in the United States, carries unresolved wounds from her abrupt breakup with Hiro Iokawa during their university romance. His sudden silence after returning to Japan for his parents’ funeral—and his unspoken duty to care for his adoptive sister, Karada—haunts her reencounter with him. A fateful visit to a shrine’s legendary wishing stone spirals into chaos when her subconscious longing to shed adult responsibilities collides with Karada’s explicit wish for maturity, magically swapping their physical ages. Trapped in an eleven-year-old body, Shōko scrambles to secure essentials like clothing and glasses while masking her identity, her guarded demeanor slowly thawing through an unexpected kinship with Karada.

Forced into proximity after moving into Hiro and Karada’s home, Shōko navigates dual challenges: demanding accountability from Hiro for his past abandonment and adapting to her childlike existence. The manga amplifies these trials, inventing a fabricated younger-sister persona to explain her transformation and teasing cryptic ties to Karada’s biological mother through their shared resemblance. Rival claimants to the wishing stone’s power further complicate her path.

While both adaptations chart her journey toward reconciling with Hiro, confronting suppressed vulnerabilities, and forging an identity independent of romance or societal roles, their tones diverge. The anime culminates in emotional closure and renewed bonds, whereas the manga lingers in darker territory, extending the age swap’s repercussions and probing existential questions left unanswered on screen.