Shiroishi Ryo, a salaryman who has been living off his savings from social games, is summoned as a hero and obtains the Gift (Skill) 'Gacha'. However, the king, unable to gauge the value of this skill, imprisons Ryo. Upon learning that he is to be used as a sacrifice for the next summoning, Ryo decides to escape the castle using the skills obtained from Gacha and leave the country. In the process, he takes some of the castle's treasures as compensation, which ends up significantly altering the world. Unaware of the consequences, Ryo, feeling the corruption of this world, decides it is not worth saving and chooses to live as he pleases.