In a dark and twisted world where religion and belief clash with the supernatural, a young priest is thrust into the heart of an ancient conflict. This priest, skilled in the arcane arts of exorcism, finds himself questioning the very foundations of his faith as he is confronted with a malevolent force that the church has long sought to keep hidden. His journey begins when he receives news of the mysterious death of his mentor in Rome, driving him to seek answers and justice. Accompanied by a troubled young woman with a haunted past and a fellow priest, he ventures into a realm where heresy and age-old secrets intertwine, revealing a conspiracy that challenges the highest echelons of religious power.

As they delve deeper into the mystery, they encounter a forbidden sect known as the "Sin Eaters," who possess the power to absolve the sins of the dying, thus granting them access to heaven without the church's intervention—a practice considered heresy. This discovery leads the priest into a direct confrontation with the very core of his beliefs, forcing him to redefine his understanding of redemption and the nature of evil. Meanwhile, the sinister forces at play have their own agenda, drawing him into a deadly game of faith versus sacrilege, where the true nature of salvation and damnation is revealed.