Hiroshi Zenno is an average high school student whose only talent lies in arcade games. One day, after setting a new high score of over nine hundred million in his favorite game, he happens upon an advertisement for a new game called "Expers." The game promises both amazing gameplay and a chance of winning the affection of the beautiful Princess Atover, so Hiroshi signs up to play.

The next day, Hiroshi is at school when a mysterious capsule crashes into his classroom, within it containing Princess Atover herself! She gives Hiroshi a powered suit that grants enhanced abilities and tells him that he is the main character of a video game, naming him "Zenon." Unfortunately, in order to win, Hiroshi must defeat all of his opponents—other players with a desire to become the "main character" of the game. Will Hiroshi be able to survive this deadly game and uncover its true nature?