Tennis no Oujisama: Sonzoku Yama no Hi

The Seishun Academy tennis team heads to a mountain club for a one-day training camp, only to discover that the schedule is packed with exhausting drills tailored to each player's style. Failure also carries an especially unpleasant penalty: another of Inui's terrifying experimental drinks.

The training is interrupted when a group of arrogant university students tries to take over the courts reserved for Seishun. Rather than surrender the space, Ryoma Echizen challenges them himself, turning a supposedly simple camp into another test of confidence, stamina, and tennis skill.