Black Death opens with a haunting voiceover from Wolfstan (John Lynch), a soldier tasked by the Church in 14th Century England. As an enforcer of divine justice, Wolfstan and his fellow soldiers are on a relentless mission to hunt down those who stray from God's path. The film begins amidst the turmoil of the bubonic plague, which ravages the population and inspires widespread belief that it is a punishment from God cast upon the sinful. However, Wolfstan ponders whether such an extreme punishment can truly be justified, probing the depths of human sin and its consequences.
In this turbulent time, we meet Osmund, a young novice monk. He is sent into a nearby town on a task, where he encounters Averill, a captivating young woman who harbors deep feelings for him. Fearing for her safety as the plague spreads, Osmund implores Averill to escape with him into the safety of the forest. She pleads with him to join her, promising to wait for him each dawn by a specific landmark, for just one week. This heartfelt exchange leaves Osmund torn between his love for Averill and his sacred vows to God. In a moment of desperation, he kneels in prayer for guidance and clarity regarding his conflicting emotions.
The plot thickens when Ulrich, an aide to the local bishop, leads a troop of Church soldiers to the monastery where Osmund resides. They seek a monk to guide them on a perilous journey to a remote village rumored to be free of the plague. Seeing this as the divine sign he prayed for, Osmund eagerly volunteers, knowing the expedition will lead them through the very forest where he urged Averill to hide.
As the group travels through the somber woods, they stumble upon villagers preparing to execute a woman accused of witchcraft (Marianne Graffam). Ulrich intervenes only to end her life quickly, arguing that the villagers would have done much worse otherwise. The soldiers proceed, eventually setting up camp in the forest. Eagerly, Osmund rushes to meet Averill at their predetermined spot, only to discover her scarf and a gang of bandits. In a chaotic turn of events, the brigands attack the camp. Though the soldiers manage to fend them off, many horses are stolen, necessitating their journey to continue on foot.
Upon reaching the village, they are greeted by Hob (Tim McInnerny), who offers them hospitality for the evening. As Osmund, now injured, receives care from Langiva, the village herbalist, it becomes evident that the serene facade of the village conceals darker truths. Langiva, seeing through Ulrich's facade, reveals her underlying resentment towards the Church, which caused her personal loss. She later unveils a startling discovery—sacrifice effigies of the last Church party that attempted to punish the villagers. Then, in a shocking revelation, she pulls Averill’s body from a shallow grave, intensifying Osmund's grief.
The narrative escalates into a harrowing conflict where Ulrich finds himself amidst a witch-hunt of a different kind. The villagers, believing themselves free from the Church's oppression, turn the tables on the soldiers. Their drugged dinner leads to each soldier facing trial at the hands of the villagers, exposing a grim reckoning. Frith (Thorsten Querner), one of the soldiers, faces a brutal death when he refuses to renounce his faith, only to be disemboweled.
As chaos unfolds, Osmund navigates the complexities of love and loyalty, ultimately confronting Langiva again within her home. Here, he finds Averill alive but in a deeply altered state, prompting him to make a tragic choice to end her suffering, believing she has been cursed. Langiva, enraged by the Church's continued oppression, takes matters into her own hands, and Ulrich faces a brutal end, exposing the devastating impact of the plague he brought upon the village inadvertently.
In the aftermath, as battles rage and loyalties are tested, Wolfstan reflects on the fate of the remaining characters. As he journeys back to the monastery with Hob in custody, he acknowledges the irony of a village untouched by the curse of the plague, attributing their survival to isolation rather than witchcraft.
In his poignant closing monologue, Wolfstan acknowledges the tragic transformation of Osmund into a vengeful figure of the Church. Osmund’s grief spirals into madness, fueled by his relentless pursuit of Langiva, whom he sees as the root of his anguish. This relentless drive propels him into becoming an inquisitor, enacting merciless vengeance on those he perceives as witches, embodying the very horrors he once sought to combat.
As the story reaches its haunting conclusion, Wolfstan's voice resonates with a painful prayer for Osmund's redemption, even as he partakes in the grim execution of innocents—a cycle of violence that leaves the audience pondering the true nature of faith and humanity's darkness. The film concludes with a powerful fade to black, leaving behind lingering questions about morality, belief, and the cost of fanaticism.
