Sana Aiwa is a bright and energetic schoolgirl. Due to her parents reasons, she transferred to the St. Etoile Municipal School.

On her first day at the school, she is called to the classroom by the teacher for formalities. When she sees Ai Kanbara being bullied by Benai Kanouma, who is sitting next to her, she can't stand to stay and intervenes.

On the way home, Sana learns that Ai was bullied because she has a rare model of the legendary "Angelmaker" game machine, which has become an urban legend. Moreover, Ai had two of them in her possession.

Ai tries to give one of them to Sana as a sign of friendship. Sana refused, saying she couldn't accept such an important thing. Sana listens to Ai's explanation and immediately goes through the initial settings. At that time the angels they were raising suddenly appeared from their game console as if they were 3D images.

"Protect us, raise us, and in return, we'll give you our mysterious power."

At that moment, the two are suddenly attacked by an unidentified monster that looks like a demon. They try to escape, but Ai cowers and when Sana tells her to turn on her heel, her legs tangle and she falls. The intestine-like tentacles bounced off Sana, who tried to help her and went straight to tangling in Ai's legs and started dragging her.

"If I can save Ai-chan, I'll do anything!"

Sana clutched at straws and pressed the Angelmaker button.