In the heart of Salem, Massachusetts, Heidi (Sheri Moon Zombie), a recovering drug addict, starts a new chapter in her life as she spins records at a gritty rock radio station, joined by her friends Whitey and Munster. One fateful day, she receives a mysterious wooden box that holds an album from a band called The Lords, whose musical composition consists solely of strings and woodwinds. Upon listening to the haunting melodies of the record alongside Whitey, they find themselves unexpectedly transported into a sinister alternate reality where women are ensnared by malevolent forces and are ritualistically giving birth to a cursed child.
The day after this eerie revelation, Heidi conducts an interview with Francis Matthias (Bruce Davison), a writer who has penned a book about the infamous Salem witch trials. As The Lords' album resonates through the radio waves, a surreal trance descends upon every woman in Salem. Megan (Dee Wallace), the palm reader and sister of Heidi's landlady, ominously informs her that she is destined to succumb to her hidden cravings. Intrigued and disturbed, Heidi begins experiencing unwanted visions that lead her to apartment 5, where unsettling glimpses of a demon and a witch chanting, "Bleed us a king," haunt her mind.
Amidst her struggle to comprehend these bizarre phenomena, Heidi seeks refuge in Francis' company. As he dives deeper into his investigation, he uncovers ancient melodies hidden within the pages of an old book. This alarming discovery reveals that the haunting tune of The Lords was crafted centuries ago by a group accused by Rev. Hawthorne of witchcraft, who believed it had the power to control the women of Salem. As legend has it, the coven's leader, Margaret Morgan (Patricia Quinn), laid a curse upon Hawthorne's lineage, foretelling that his descendant would be the "vessel through which the devil's child would inherit the earth." Shockingly, it unfolds that Heidi is a direct descendant of this very bloodline.
As the nightmarish visions continue to oppress her, Heidi becomes increasingly ensnared by her drug addiction, seeking a means to escape the torment that encroaches upon her. In a desperate attempt to find salvation, her landlord Lacy and her sisters, Sonny and Megan, guide her to apartment 5. What appears to be an extravagant opera house manifests within its confines, dominated by a professed demonic throne. There, Heidi is ensnared by tendrils of darkness, facing the malevolent force that has long plagued her existence.
On the following day, Matthias attempts to reveal the shocking truths about The Lords and Heidi's unnerving lineage but is met with sinister resistance from Lacy and her sisters, who violently silence him. Oblivious to the chaos occurring around her, Heidi remains in a paralyzed state. As night falls, an ominous concert featuring The Lords begins, and Heidi becomes unwittingly entangled in a ghastly ritual alongside Lacy, Sonny, Megan, and spectral figures of Margaret and her coven. To the sound of The Lords' enthralling music, the women in the audience fall into a hypnotic trance, stripping off their clothing as if succumbing to nature itself.
In this haunting tableau, Heidi finds herself confronting primal forces, culminating in the birth of a grotesque, crustacean-like entity amid the chaos. The grotesque aftermath leads to devastating revelations – reports stream into the radio station about a mass suicide at a rock concert, coinciding with the inexplicable disappearance of its star anchorwoman, who is none other than Heidi herself.
