The Nun 3 continues the terrifying saga of Sister Irene as she once again faces the demonic force known as Valak. The film begins in Italy, where a series of gruesome murders within sacred sites spark fear across the Catholic Church. Each victim is a priest or nun tied to a secret order sworn to contain Valak centuries ago. When the Vatican realizes the killings form a pattern pointing toward an ancient prophecy, Irene is called back to confront the evil she thought she had banished.

Haunted by visions and plagued by doubt, Irene journeys with Sister Debra to a crumbling monastery in Eastern Europe where the first traces of Valak’s power emerged. The locals whisper of shadows moving through the woods at night and children vanishing without a trace. As the two nuns investigate, they uncover disturbing relics, strange symbols burned into the walls, and a hidden chamber that holds the key to Valak’s resurrection.

Unlike previous encounters, Valak is no longer content with mere possession or haunting. This time, the demon seeks to manifest fully in the mortal world, feeding off centuries of fear and blood sacrifices. Irene realizes that the murders are part of a ritual to restore Valak’s power and open a gateway of darkness. The more they uncover, the clearer it becomes that Valak is manipulating not only the physical world but Irene’s own memories, twisting her faith and making her question whether God will stand by her side.

The horror intensifies with chilling sequences—corridors that shift into endless voids, candles snuffed out by unseen hands, and spectral figures lurking behind every door. One particularly harrowing scene shows Irene trapped in a hall of mirrors, each reflection revealing a different form of Valak. The atmosphere is drenched in dread, amplifying the sense that no sanctuary is safe, and that even holy ground is corrupted by the demon’s reach.

As the climax approaches, Irene discovers that the only way to defeat Valak is not through banishment but through sacrifice. She must destroy the ancient relic binding Valak’s soul, even if it costs her life. With Sister Debra’s aid, they wage a desperate battle inside the monastery’s catacombs, where the boundary between the living and the damned begins to collapse. The confrontation pushes Irene to embrace both her human vulnerability and her divine calling.

In the final act, Irene channels a strength that transcends fear, using the relic’s destruction to sever Valak’s hold. The monastery collapses in fire and shadow, and though Irene survives, the ending leaves a chilling ambiguity: Valak’s laughter echoing faintly, suggesting that true evil never dies. The Nun 3 thus closes as both a battle won and a warning of darkness yet to come.