Mary Shelley, portrayed by Elsa Lanchester, the brilliant mind behind Frankenstein, or The Modern Prometheus, recounts to Percy Shelley (Douglas Walton) and Lord Byron (Gavin Gordon) an extraordinary revelation: both Henry Frankenstein (Colin Clive) and his towering creation, the Monster (Boris Karloff), have astonishingly survived. Their journey continues, laden with even more bizarre adventures than those chronicled previously.

The story unfolds with flashbacks to the events in Frankenstein (1931). In a pivotal moment, following the catastrophic collapse of a mill—thought to be the Monster’s destruction—the Bürgermeister (E.E. Clive) implores the townsfolk to return home. However, a grieving father (Reginald Barlow), burdened by the loss of his daughter—the unfortunate victim of the Monster—craves closure by witnessing the creature’s lifeless form. Despite the protests of his wife (Mary Gordon), he braves the burning ruins, only to fall through a concealed opening, plunging into a submerged cavern. In a tragic twist, the Monster emerges from the depths, resulting in the father’s death, and later claims the mother’s life as well. The devoted servant Minnie (Una O’Connor), likewise encounters the Monster but manages a narrow escape, leaving her warnings to deaf ears as no one believes her accounts of the lurking horror.

Henry dreams of a tranquil existence alongside his new bride, Valerie Hobson. Yet, the return of his former mentor, the malevolent Dr. Pretorius (Ernest Thesiger), disrupts his plans. Disgraced but determined, Pretorius persuades Henry to resume his perilous quest of granting life, showcasing his own diminutive creations, which he refers to as living experiments barely measuring a few inches.

As rumors of the Monster’s continued existence spread throughout the village, the creature is captured. However, his might and tenacity allow him to break free, leading him into the depths of the forest as the villagers pursue him relentlessly. In a serendipitous encounter, the Monster stumbles upon the rustic abode of an elderly blind hermit (O.P. Heggie), who, while delighting in the melodies of his violin, becomes an unexpected companion to the lonely creature. Together, they experience the pleasures of life—music, cigars, bread, and wine—while the Monster, understanding human speech, begins to learn how to communicate. This brief episode of joy is fraught with peril as two chance visitors come upon them, recognizing the Monster. In the ensuing chaos, they inadvertently set fire to the hermit’s home, leaving the Monster to flee once more, heartbroken.

Fate intervenes in the darkened crypt, reuniting Dr. Pretorius and the Monster. Here, Pretorius cunningly employs the creature to abduct Mrs. Frankenstein, coercing Henry into returning to his castle to fulfill the sinister demands of his experiments. Desiring companionship, the Monster implores Henry to craft him a mate, while Pretorius aspires to animate a female figure from dead tissue. Reluctantly, Henry is compelled to create a “Bride” for his original creation, embodied once again by Elsa Lanchester. However, their union is fraught with tension, as the Bride reacts with terror and horror towards the Monster, causing him immeasurable despair. Despite his nurturing aspirations, the Monster ultimately liberates Henry and his wife from Pretorius’s clutches, initiating a catastrophic explosion that obliterates the castle, along with himself, his bride, and Pretorius.

Yet, the saga of the Monster does not conclude there. The anticipation builds for the next chapter in this ongoing tale as we learn from Het monster van Frankenstein (1939) that the Monster, against all odds, has once again managed to survive.