A poor college student, Arisa Miwa, is transported into the body of Aisha, a super-rich duke’s daughter in a video game world. Before her appears a cat calling itself the "Heel System", commanding her to act as a villainess and cause trouble for various people—starting with the heroine, Lucy.

Arisa tries to follow the instructions, but things don't go quite as planned: Though she tries to bully Lucy, she ends up saving her life. Though she intends to harass a maid, she accidentally helps her out of a difficult situation. When she tries to torment orphans, she inadvertently gives them a chance to become independent.

Meanwhile, Prince Clarice, who observes Arisa’s actions, invites her to a ball. There, the two end up becoming engaged, and Lucy—who was originally destined to be with Clarice—starts down the path of becoming a knight instead.

Will the game still be able to reach its happy ending...?