Rio has been taking care of herself and her brother since her parents passed away during her youth. She has always been self-reliant and trusts no one completely. One day, she purchases a trump card featuring the jack of clubs, styled after Sir Lancelot, with the intention of selling it for a profit online. However, Lancelot begins to appear in her dreams every night after the purchase. When a friend named Yuuki-kun asks her out and attempts to kiss her, Lancelot suddenly materializes and declares that he has come to rescue Rio.
