Two children open a sealed door and find a demon named Chrno sitting inside the building. He tells them that that they should fear him, but he collapses from hunger. Rosette offers him some food and Chrno accepts, surprised. Josha tells him how cool it is that Chrno is a demon. When Chrno looks up, he sees Aion. Joshua starts to walk away and then turns to mist. Rosette wakes up from her dream and misses her brother. At mass, the other sisters tell Rosette that they think Chrno is handsome. She is embarrassed that they think she and Chrno are a couple.

After mass, Rosette heads over to the Elder's office. He shows her some Spirit bullets that he is developing and asks her to take them to Sister Kate. He tells her that there are demons in those rounds. He has managed to break down demons into a spiritual energy and on impact with another demon, they explode. Rosette is tempted to try out the bullets and instead of delivering them to Sister Kate, takes them on her next mission.

She and Chrno go after a horned demon - Chrno tells her that if she aims for the horn, she can defeat it. The demon's horn explodes and it falls to the ground. Rosette loads up a Spirit bullet, but before she can fire it, the demon knocks the gun out of her hand. However, it crumbles to dust before it can attack her. Chrno gets a strange feeling, but tries to brush it off. After they defeat the demon, Chrno and Rosette look for her gun. A demon who has been disguised in the crowd has taken it.

Back at the Order, Rosette reports that the owner of the establishment worshipped demons. Remington asks her what she did with the horn and she replies that she gave it to the Elder. Sister Kate congratulates her for finally completing a mission where she did not destroy anything in the process. When she goes to see the Elder, she finds that he is developing a machine that will sense the presence of demons. Remington follows her down and she apologzies for having lied to him. He tells her that it is all right. The Elder presents them with the machine. When they turn it on, they find that the Spirit is close by.

Outside, the demon who stole her gun blasts through the doors of the Order. He sets off alarms and walks forward. Rosette and Chrno run out and they realize that the person is not a human but a demon. He walks forward, holding Rosette's pistol, and shoots himself in the head. Rather than dying, he emerges as a more powerful demon. The other nuns fire at the demon, but it only makes him grow more powerful. Chrno realizes that he is using the energy from the Spirits, rather than from his missing horn.

Chrno holds up the horn and distracts the demon while Rosette loads her gun. As she goes to fire, she realizes that she loaded it incorrectly. The demon sends her flying, angering Chrno. Chrno begins to change, fighting against his seal. Before he can fully change, Rosette tackles him and brings him back to reality. She then kills the demon. Sister Kate, the Elder, and Remington are all worried about Chrno, wondering if he will ever break the seal. Meanwhile, Joshua receives word from Fiore that Aion wants to see him. Before he can see Aion, Viscount Borzo, a huge demon, steps in. Joshua asks Fiore to get some coffee. When she comes back, she finds Borzo dead on the ground.