Yuuri Shibuya is an average high school student whose passion in life is baseball. On his way home from school one day, Yuuri spies his classmate, Ken Murata, being harassed by a group of boys. He decides to help and calls out to the bullies. When the bullies notice him Murata runs away. The bullies drag Yuuri to the girl's bathroom to dunk his head in a toilet for letting their prey escape. However, something strange happens and Yuuri finds himself getting flushed into another world. When he reaches dry land, he sees some people dressed in medieval costume. He assumes that it is a theme park. However, the people are afraid to see him and begin to pelt him with stones. Conrad Weller and Günter von Kleist rescue Yuuri and take him to Blood Pledge Castle, the residence of the Maou. He meets some key characters, his fiance Wolfram for one, and soon finds himself being called the 'Maou', or Demon King. There, Yuuri learns he is to be crowned king and rule over 'Shin Makoku'.
Throughout the series, Yuuri is constantly confronted with the results of even the smallest choices he makes. With a strange power dwelling inside of him, Yuuri becomes a deliverer of justice in the world of Shin Makoku.
by wikipedia
>> Rewind?