It's an anime based on the martial arts video game, originally created for the Sega Saturn. The story revolves around Yuuki Akira, the martial arts expert who uses Hakkyoku-Ken.  Though you might not think it when you play the game, in the anime Akira is kind of a goof, always thinking of his stomach and very easy-going.  If he is pressed to fight though, his whole attitude changes and he becomes the calm, composed fighter of Sega fame. 
    Pai Chan, Sarah Bryant, and Jacky Bryant are also central to the anime's plot.  They meet in the early episodes and travel with Akira for the whole series.  In fact, the major story arc concerns Sarah Bryant being kidnapped and brainwashed.
    The other characters of Virtua Fighter also make cameo appearances, though a couple show up in more than one episode.