The story tells us about Sister Clara, who lives together with the other sisters in the Abbey. A series of strange events lead the sister to inform the Church about what happened there.
A demon has the clergy in fear. The Church contacted Father Eusebio, an expert demonologist, who promptly contacted the sisters.
Sister Clara warns him:
"Father, we need help, we see a sister who looks like us, but is not one of us, she is something impious!"
After the sister's stories, Father Eusebio begins to investigate the story. Discover a terrible fact: centuries before a demon was sandwiched in the walls of the Abbey of Santa Clara.
Father Eusebio, worried that Clara does not show signs of life, decides to ask the inhabitants of a nearby town for help, to see what really happens there.