Akira Ouno is a regular guy who works at a company that manages an online game. He often plays the game as his character "Maou" (Dark Lord). But one day, when he logs on, he is whisked into the game's fantasy world as his character. There, he meets a one-legged girl, and begins his adventures alongside her. But as he is a powerful "Dark Lord," various nations and holy maidens journey to defeat him, and he stirs up trouble everywhere he goes.
[Source: Anime News Network; emended]