Keica

In a future where commercial space travel has become a reality, Cetacea Aviation employs space attendants trained in hand-to-hand combat to neutralize hijackers. Aoi Musashino, one such attendant, is clumsy and given to self-deprecation. Aoi's path crosses with a boy named Laika, who is convinced that his songs bring misfortune to those around him.

After the National Middle School Tennis Tournament wraps up, twelve-year-old tennis prodigy Ryouma Echizen heads to the United States to sharpen his abilities. While striving to forge his own path in the sport, Ryouma is also determined to uncover the mystery surrounding his father Nanjiro's sudden departure from professional tennis. Known as "Samurai Nanjiro," his father was a celebrated player whose career came to an abrupt halt after the US Open finals. Despite Ryouma's thorough analysis of that final match, many questions linger, driving him to seek answers by witnessing the event firsthand. Through a strange twist of fate, Ryouma and his unsuspecting classmate Sakuno Ryuzaki are sent back in time to observe the pivotal match. Though the early moments appear ordinary, the mafia's involvement adds a fresh, complex layer to the enigma. Facing considerable obstacles, Ryouma must employ all his abilities to uncover the truth and stop his father's career from ending prematurely.