Shinomiya Ryouma is working frantically to raise a billion yen for his sister's medical bills, while going to high school. One day, a mysterious woman asks him, "Would you put your life on the line for what you desire?" After receiving a ticket from her, he gets caught up in a fatal accident. When he wakes up, he finds he's turned into a girl and what's more, he's participating in a "game" where a win means he can reverse his fate but a loss means he'll die instantly.