Big Battle is a one-shot OVA set after the climax of the original Votoms storyline, but before the epilogue at the end of the series itself. With the Gilgamesh and Balarant forces still trying to advance their PS programs, Chirico and his old friends are forced into one last gladiatorial battle against a special PS and a formidable land battleship.

Agent Kate Lee Jackson of the GPP (Space Police) frees the mute girl Muna from a prison on the Bentika Empire, a huge floating satellite. She also frees Bavi Stock, a young boxer jailed after accidentally killing an opponent and is in danger of being killed by the brutal prison regime.

Chirico Cuvie is reunited with others from the Red Shoulder unit as they pursue their revenge against Yoran Pailsen. Unknown to them, Yoran and his group have created the Perfect Soldier, Ypsilon.

High school freshman Hiromi joins the tennis club because of her admiration for Ryuzaki. Ryuzaki is a senior, who's the best tennis player on the team and also nicknamed "Ochōfujin", ("Madame Butterfly"), because of her elegance on the tennis court. However, the new coach, Jin Munakata, wants the inexperienced Hiromi to play in a forthcoming tournament.

Mumyo Tsunataro killed his betrayed fiance Orie and He flees to Utsunomiya. On his way he happens to saves Chisaka Hyobu's daughter Oyu (She is exactly like Orie) be attacked by ninja. Thus he stays Chisaka's residence in Yonezawa. Chisaka was just trying to stop Forty-seven ronin's revenge against Kira Kozukenosuke by female ninja's sexual entrapment. Chisaka asks Tsunataro to lead female ninja. Tsunataro accepts the request on condition of marriage to Oyu.

Jiban goes into action to save Yoko and several captured children from Doctor Giba's plot of creating the ultimate lifeform.