Tennis no Oujisama: Message in a Bottle

At Rikkai University-Affiliated Middle School, the boys' tennis team encounters an intriguing mystery when they discover an unusual bottle floating in the river. Inside, they find a puzzling message that invites them to contribute an item of their own before returning it to the water. Eager to participate in this unexpected adventure, the team carefully repairs the bottle and adds a few treasures of their own, sending it off on its journey.

However, the bottle's voyage takes an unexpected turn when it washes up on the shores of Seishun Academy, where a different group of tennis enthusiasts uncovers its secrets. As the two teams become entwined in this whimsical exchange, the story unfolds with humor and camaraderie, showcasing the spirit of friendship and sportsmanship that transcends their rivalry.