In the shadowed corridors of Saint Dymphna’s Convent, where the incense hung heavy as a half-remembered sin, Sister Agatha kept a secret that would have made the Vatican weep. The year was 2021, and the manga adaptation of The Nun’s Secret had just been banned in three countries. But the true story—the one not drawn in ink or pixels—was far more terrible.

The series is noted for its "slow-burn" pacing, where the horror builds through unsettling interactions rather than immediate jump scares. It has been compared to other psychological thrillers that critique institutional power.

: Upon arrival, she is welcomed by a kind and handsome priest. However, she quickly discovers his secret: he is actually a demon in disguise.