After breaking off the engagement, Prince Cedric seizes all of Aileen's businesses. Aileen is in danger of being disowned and becoming a commoner if she doesn't recover the financial losses of the Dautriche family before the ball in two months...

Aileen finds out that Claude's aide, Keith Eigrid, has been selling demons. Keith tells Aileen about the reason why and reminisces about their past. Now that Aileen knows his true feelings, she decides to cooperate with Keith to prevent Claude from despairing about humanity and turning into a demon. At the same time, Cédric and Lilia visits the demon lord's castle to tell Claude Keith's secret?!

James turns into a demon at a different point from the original game, but Aileen decides he can still revert back and lets him escape. However, the student council member Walt Lizanis witnesses the scene and begins to doubt Aileen's identity. In turn, she exposes Walt and Kyle Elford's true identities and their mission. They decide to temporarily work together to solve the vampire case. Meanwhile, Mische Academy receives another statement from Ashtarte...

Knowing that the prize of the contest for White Lily Princess is demon incense that's harmful to demons, Aileen removes her male student disguise and enters the contest dressed as a woman. While others are overwhelmed by her beauty, James asks her to dance. The light dance steps of the pair fascinates the audience and Aileen is chosen to be the White Lily Princess. However, right after that, the mastermind has demon incense scattered throughout the venue. Aileen and the others struggle in vain as James turns into a demon.

Claude loses his memory and magical powers, returning him into a normal human being. In order to show the appeal of that aspect to the public, he goes on an inspection of the third zone of the imperial capital. During this time, Aileen follows Claude and tries to confirm her position as his fiancée. However, she just ends up experiencing the bitter feelings of a one-sided love. When she returns to the demon lord's castle, she finds the heroine of Regalia Of Saints, Demons, and Maidens 2, Selena Gilbert, fighting for demon incense with Auguste Zelm, the official hero...

Aileen falls into the sorcerer's village. While she is imprisoned, she finds out that this is all part of a coup d'état planned by the Levi family and that Lilia instigated their actions. Aileen discovers that Lilia has been secretly serving the empress dowager and she escapes the prison after winning Elephas, who has been branded as a traitor, over to her side. The two of them rush to the imperial palace to save the doomed Levi family and Claude. However, Lilia stands in their way with another holy sword in her hands.