Shiori Senozawa is the princess of the secluded mountain village's Seven Night Festival, inspired by Tanabata traditions. Participants don traditional garments integrated with augmented reality glasses that grant knowledge and enhance physical abilities for festival tasks. She guides newcomer Shoma Mihara, explaining the environment and aiding his adjustment to village life. Her responsibilities include overseeing festival preparations and welcoming attendees.

Driven by the need to reunite with her deceased sister, Kaori Senozawa, Shiori participates in the festival. This event utilizes data from the Starlight Pilgrimage mobile app to create temporary virtual recreations of the deceased, offering participants closure. During preparations, Shiori collaborates with Kanna, the artificial intelligence managing festival systems. Kanna supplies Shiori with a specialized energy bow and arrow to combat hostile entities.

Samurai manifestations, born from corrupted historical data within the festival's AI and emerging from nearby castle ruins, attack the village, perceiving villagers as enemies. Shiori actively defends against these threats using her bow—a weaponized program capable of deleting the samurai's source data. She fights alongside Shoma, targeting the samurai leader, Kogetsuhime. Defeating this leader ensures the festival proceeds.

At the festival's culmination, Shiori interacts with the virtual reconstruction of Kaori, granting her long-awaited closure regarding her sister's death. The technology typically reconstructs individuals deceased within two years, though system modifications permit exceptions. Following this confrontation and farewell, Shiori concludes her involvement in the event.