Kamishiro Aki awakens in the world of The Prince of Tennis, a realm where high schoolers wield supernatural tennis abilities. Expecting to find himself in the pirate-filled seas of One Piece, he is initially dismayed to discover his ordinary skills cannot compete with the genre's prodigies. Just as despair sets in, the God-Level Extraction System activates, granting him a novice gift pack.

In a twist of fate, his extractions pull exclusively from the One Piece universe, bestowing upon him the legendary Six Powers of Marine Vice Admiral Garp. Now armed with superhuman speed, strength, and agility, Aki transforms the tennis court into a battlefield of overwhelming power. After a violent encounter with a bully at Seishun Academy reveals the destructive potential of his new abilities, he decides to transfer to the wealthy Hyotei Academy.

There, he aims to monetize his skills through sparring fees while mastering the fusion of Haki-infused martial arts and professional tennis. The journey of the Tennis Emperor has just begun, promising to shatter every existing record and opponent in his path.