Momo Yaoyorozu is a musical prodigy set to perform at the prestigious UA Opera House.The Opera House is rumored to be cursed by something known only as the Count. Sabotaged performances and even isolated murders plague the prestigious Opera House.  One day, Yaoyorozu practices her violin and sings her lines in front of a few people. They include Aoyama, her fiance Tenya Iida, her lifelong best friend Kyoka Jiro and Aoyama's servant Yosetsu Awase. As she practices, a strange organ sound is heard in the distance. 

Aoyama: No! Not again! Not the Count!

Suddenly, smoke begins to fill the area where Yaoyorozu was everyone becomes concerned.

Iida: What's going on?!

Iida and Awase go to the smoke but find Yaoyorozu gone without a trace. 

Awase: She's not here!

Iida: That's impossible! 

Sometime after, Yaoyorozu wakes up in a room surrounded by beautiful paintings. She gets up and looks around the room she's in. As she does so, she begins to hear the same organ music she heard earlier. She follows the music and sees a man with red and white hair playing away while singing.

Yaoyorozu: Hello?

The man turns to Yaoyorozu and his left side is covered in a white mask. She doesn't know what to make of it. 

Masked Man: My name is Shoto Todoroki. Welcome to my home.

Yaoyorozu: Shoto Todoroki? I've heard of you! You were a famous Opera Singer!

Todoroki: That was.....another life. Now they call me the Count.

Yaoyorozu: What happened?

Todoroki: Lies. Deception. Treachery. 

Todoroki rand his hand on his pale mask. Yaoyorozu couldn't help but feel pity for the man.

Yaoyorozu: Why am I here?

Todoroki: I heard your music. So beautiful and so elegant. My heart fell for you from the moment I saw you. But first, I will avenge the injustice done to me by Aoyama! 

Yaoyorozu was stunned by Todoroki's confession and heard his desire for vengeance against Aoyama. She had no idea about what happened. 

Todoroki: I will take everything he holds dear! First his Opera House and then his life! He stole everything from me! His punishment shall be tenfold! The Count is known as a curse, I will make it real!

Yaoyorozu was speechless by his rage. She had heard rumors of Aoyama's shady behavior, but she couldn't fathom the suffering Todoroki accused him of. 

Yaoyorozu: I.....I......I have to go......

Todoroki: I want you to promise me that you'll always be faithful to me. Please!

Yaoyorozu: Please! You're.....you're hurting me!

Yaoyorozu felt fear as Todoroki grab her hand. But he soon calmed himself and let go.

Todoroki: Go. Continue to make beautiful music. But know that my heart is yours. Take this flower as a token of my love.

Todoroki led Yaoyorozu to the exit of his hideout after giving her a Red Rose. Afterwards, she reunited with her fiance and her best friend.

Iida: There you are Momo! When you disappeared, I felt lost!

Jiro: What happened?!

Yaoyorozu: I....I don't know.

The next day, Yaoyorozu woke up and practiced her violin when Aoyama entered the room.

Yaoyorozu: Aoyama! What brings you here?

Aoyoama: I wanted to check up on you. It must've been quite an ordeal you went through!

Yaoyorozu: I don't remember much of it. May I ask you something?

Aoyama: What is it?

Yaoyorozu: What do you know of Shoto Todoroki?

Hearing that stunned Aoyama. 

Aoyama: Todoroki was a....brilliant Opera Singer. We had our disagreements. But one day, he died in a fire. 

Despite hearing that, she knew the truth. Todoroki did not die in a fire. She also knew that Aoyama was hiding something. Aoyama exits the room as Iida comes in. 

Iida: I can't wait to marry you Momo! 

Yaoyorozu: Tenya.......I was kidnapped by the Count.

Iida: What?!

Yaoyorozu: I want you to promise me that after the performance, we leave far away from here. 

Iida: I promise my love.

As they kissed, Todoroki saw from a window outside on a balcony.. When they left, Todoroki entered the room where he recoiled in his heartache. The woman he loved has rejected his love. Sorrow was followed by great rage. 

Todoroki: You will curse the day you did not do all that the Count asked of you!

Todoroki then interrupted by Awase.

Awase: Hey! You're not supposed to be up here!

Todoroki: That is none of your concern!

Awase then attacks Todoroki, but Todoroki overpowers him and pushes over the balcony, sending Awase plummeting to his death. Jiro sees Awase plummet to the ground and screams. 

Jiro: Help! Someone's fallen! HELP!

Aoyama and Iida run to where Jiro and sees Awase's broken body. 

Iida: My God! We need to cancel the performance! 

Aoyama: We can't! Everything is already set up! It must've been an accident.

Iida: You better be right about that! I'm not putting my fiance in danger because of your ego! 

Days later on the eve of Yaoyorozu's performance, a male lead singer by the name of Sen Kaibara prepares for his part in the performance when Todoroki enters the room.

Kaibara: Hey! Who are you?!

Todoroki says nothing as he pounces on him and strangles him to death. When the performance began, Yaoyorozu's began to play her violin. As she plays her violin, Todoroki appeared and began to sing where Kaibara was supposed to be. 

Todoroki(Singing): Anywhere you go, let me go to!

As he sang, Yaoyorozu was left stunned by his voice. She couldn't help but feel a sense of love from the singing. She continued to play her violin. The singing from Todoroki and Yaoyorozu's violin playing blended together. Aoyama noticed something about this singer.

Aoyama: Wait a minute, that's not Kaibara!

That realization brought great concern and fear into Iida for his fiance.

Iida: Oh no! Momo!

Todoroki(Singing): Momo! That's all I ask of you!

Todoroki removed his mask to reveal a burned face on his left side. Seeing that deformity caused the crowd to scream in sheer terror. He turns to Aoyama, speechless by the revelation.

Todoroki: Aoyama! You took everything from me! And now you will burn!

As he said that, Todoroki pulled out a sword and slices the rope which held the chandeliers in place as it begins to swing. Horrified, the crowd begins to rush to the exit. The chandeliers then slams to an open area, causing the Opera House to catch fire. Todoroki then begins to chase Aoyama to the roof of the Opera House.

Todoroki: Yuga Aoyama! Vengeance will be mine!

Aoyama: How are you alive?! You were the Count?!

Todorki: I took this curse and made it my own! Every horror I inflicted here is done to destroy you! As your Opera House burns, you will pay for the injustice you've done to me!

Aoyama: The fire wasn't my fault! It was an accident! 

Todoroki: There's no escape from justice! I will have my revenge! 

Tokoroki then rushes to Aoyama and pushes him off the glass roof of the Opera House and down to the raging inferno below

Yaoyorozu: Shoto! 

Yaoyorozu then rushes to Shoto. Despite her rejecting his love, he couldn't find the rage in him. Knowing what Aoyama had done to him, Yaoyorozu could not bring herself to hate him or even fear his disfigured face. Then Iida rushes to the roof armed with a sword. 

Iida: You will not endanger her this time!

Yaoyorozu: Tenya! Please no!

Iida and Todoroki began to duel but Yaoyorozu gets in between them in an attempt to stop them.

Yaoyorozu: Please! Stop it you two! Please! 

But as Yaoyorozu got between them, Todoroki stabbed her in the chest. That attack was meant with Iida

Iida: No! Momo! 

Iida cradled his dying fiance. She puts her hand on his face. After that, she pulls out the rose, now bloodied and hands it to Todoroki. 

Yaoyorozu: I......I.......I'm......sorry I wasn't......able to.....keep that promise.......Shoto......

With her last breath, Yaoyorozu died. Todoroki dropped to his knees as tears streamed down his face. While Iida mourned for his dead love, Todoroki walks to the edge of the Opera's broken glass roof and stared into the inferno. 

Todoroki: What have I done? Damnation is all I have. Why would a wretched creature such as I deserve a love so pure? 

As he prepared to make the final leap, Todoroki turns to the grieving Iida.

Todoroki: I am sorry for what I've taken from you. I will rid the world of my wretched existence. How can I live in a world that allows such a pure and beautiful spirit die in such a way. This will be my punishment. 

Todoroki then let go as he stepped down and fell in the inferno below, killing the Count and ending his lust for vengeance and unrequited love. The horrors he committed in the name of vengeance consumed him in the end.