The story takes place one year after the "Xiaoyue Waltz" event (2036). The protagonist Soma Cruz is the reincarnation of the demon king Dracula, but he successfully defeated fate in the previous installment and did not awaken to become a new Dark Lord, living a peaceful life with his childhood friend Mina Hakuba.
However, this calmness was shattered by a woman who called herself Celia Fortner. She is the leader of an emerging cult and led her followers to attack Cangzhen. Celia believed that there must exist an 'absolute evil' (i.e. Dracula) in the world to complement her teachings of 'absolute goodness'. In order to achieve this goal, she plans to kill Cangzhen, who contains the soul of Dracula, in order to completely liberate and resurrect Dracula's power.
With the warning and assistance of the mysterious government agent Genya Arikado (whose real identity is Dracula's son Arukado), Cangzhen was once again forced to fight. He found that his ability to absorb monster souls had not disappeared, he was only temporarily asleep.
Cangzhen took the initiative to go to the cult's stronghold - a demon city that appeared out of thin air and was extremely similar to Dracula's castle - in order to completely solve the crisis.
There, he learned that there were two "demon king candidates" by Celia's side: Dario Bossi (manipulating flames) and Dmitrii Blinov (copying magic). They were born on the day Dracula was eliminated and have the potential to become the new demon king. Their goal is to kill Cangzhen, take away the Dracula soul from his body, and become the new demon king.
