 Since their mother, Ronnet, died in an auto accident and their father, Takuma left them, Ryo Sakazaki, master of Kyokugen-Ryuu (Extreme) Karate, became a street fighter to support his little sister, Yuri. But one day, Yuri mysteriously vanished. Together, Ryo and Robert Garcia, his best friend and fiercest rival, venture together into the dangerous Southtown, beating up many tough fighters to find out Yuri s whereabouts. Which major criminal is behind Yuri s kidnapping...?