Mino Saito is the granddaughter of Shozo and Ine Saito and the daughter of Yoshiaki and Kaede Saito. She lives with her grandparents in their rural Aomori Prefecture home. Mino possesses an energetic and expressive personality, frequently showing visible excitement or concern, a contrast to her more reserved cousin, Shiori Saito. She attends the local high school and becomes deeply involved in her grandparents' lives after their transformation into youthful forms. Initially shocked and concerned by their changed appearances, Mino quickly adapts and becomes protective of their secret. She actively participates in their daily routines, assisting with chores and joining them at events like summer festivals and family gatherings. Her classmate, Shota Igarashi, develops romantic feelings for her. Shozo notices this and sometimes creates opportunities for them to interact. Mino gradually reciprocates Shota's interest, leading to a courtship. Following her grandparents' passing, she marries Shota. Decades later, as an elderly couple themselves, they discover a golden apple in their orchard, mirroring the event that triggered Shozo and Ine's rejuvenation.