Reika Hoshi is a main character within the "Steady x Study" franchise and a member of the Kamimori Private Academy drama club in Harajuku, alongside Koyuki Saito and Mei Uehara. Her activities focus on club functions, including preparing for performances and practicing with fellow members on the school rooftop.

She attends a student council meeting where club funding is denied, observing the financial discussions without direct involvement. Following this setback, Reika joins her friends at a local café. Later, she accompanies Koyuki and Mei to a planned meeting in a park with Makoto Nakane. Despite heavy rain suggesting he might not come, Makoto arrives, pulls Koyuki aside for a private talk, and Reika remains part of the group dynamic throughout the encounter.

After the park meeting, Reika participates in crafting props for the upcoming drama club performance while Makoto and Koyuki resume their rooftop practice. Her documented role consistently involves supporting club activities and group interactions, without driving independent narrative developments.