SAILOR MOON SUPERS PLUS: AMI'S FIRST LOVE

Quiet bookworm of the Sailor Senshi Ami takes pride in her studies, but a rival naming himself "Mercurius" is suddenly outscoring her on the national exams. Combine this with a sudden love letter and a youma feeding on Ami's stress over the whole situation, and Sailor Mercury finds herself in a huge pinch. (Source: Anime News Network) — Description from AniList community (anilist.co).