Kiiko Shimazu, a third-grade student, moves from Tokyo to rural Mitajiri in 1955 when her father becomes a doctor at a local factory. This relocation happens as she mourns her mother's recent death, contributing to her initial reserved and introspective nature, contrasting with the more outgoing local children.

Her city background shows in possessions unfamiliar to rural peers, like a gas-powered refrigerator and expensive colored pencils. She displays a distinct fascination with technological progress and future possibilities, often envisioning advancements decades ahead. This perspective complements her new friend Shinko's imaginative focus on the area's ancient past.

Through friendship with Shinko and joining the village children's "Destiny Squad," Kiiko undergoes substantial development. Activities like building a dam for a goldfish and exploring the countryside gradually draw her out of her shell. Her journey involves processing grief and adapting to change, mirrored in her deepening connection to the imagined story of Princess Nagiko, a lonely noblewoman from a thousand years earlier. In a pivotal moment, she mentally embodies the princess, helping a village girl and resolving the historical figure's isolation, reflecting her own path toward integration and acceptance within her new community.

Personality-wise, she exhibits quiet observation, creativity expressed through drawing, and strong empathy. Analysis suggests an alignment with the INFP personality type, characterized by introspection, imagination, emotional sensitivity, and spontaneity. Her perceptive nature allows her to form meaningful bonds despite initial shyness, valuing these connections deeply.

Her character arc explores coping with impermanence, finding belonging after loss, and friendship's power to bridge personal differences. By the story's conclusion, she transitions from a withdrawn newcomer to an active participant in village life, her imaginative capacity serving as both a comfort and a means of understanding the world.