While playing the game 'The Regressor's Way to Prevent the Destruction', I fell into the game world as soon as I pressed the special event item.

I possessed Oswald Winchester, who, from the beginning, was ripped off by the regressor, kicked out of the academy, and ended up falling as a villain.

To confront the apocalypse and return to my original world, I must change the fate of the villain Oswald.