Whilst on an expedition to find a sea route through the Arctic, wealthy Englishman Robert Walton has rescued a solitary traveller who, confined to what will prove to be his deathbed, narrates the events which have brought him to it. As a youth, Victor Frankenstein of Geneva pursued an obsessive interest in the arcane applications of natural science at the university of Ingolstadt, where his research eventually revealed to him the secret of creating life itself. After labouring in secret to construct a large humanoid body into which he infuses a living consciousness, Victor immediately regrets his actions and abandons their result. Recovering from a long nervous illness he returns home to his family, but their domestic peace is soon shattered by two events: the murder of his youngest brother William; and the subsequent execution of a beloved servant Justine, who is convicted of the crime based on circumstantial evidence.
While wandering across an alpine glacier, Victor is unexpectedly confronted by his creation. The creature reveals that he engineered the tragedy, and proceeds to narrate his own brief biography by way of explanation. Since leaving Frankenstein's Ingolstadt apartment, he has learned much: from observation, the basic elements of the physical world; from his hidden residence near to a French family, not only the ability to read and speak but also the warmth of human contact; from their attacks and those of other fearful villagers, his own deformity and the eternal separation it must mean for him; and from the notes left behind by Victor, the name and residence of his creator. His murder of the youngest Frankenstein was a mere overture to the terrible vengeance the creature promises to wreak if his demand is not met: the construction of a second, female being as companion for the first, an antidote to the maddening isolation to which his ugliness condemns him.
Fearing for his family, and persuaded by the creature's vow to forego all human contact if provided with a mate, Victor travels to Britain under the pretence of a restful holiday with childhood friend Henry Clerval. In fact he seeks the knowledge of certain English scientists necessary for his work. Leaving Henry in Scotland, he retreats to an isolated island in the far north, and almost completes his second creation before repenting and tearing the unfinished body to pieces. The original creature kills Clerval in retaliation and Victor finds himself charged with the crime, only saved by the intervention of his father. On returning to Geneva, Frankenstein finally resolves to marry his cousin and long-term fiancée Elizabeth, only for her also to be murdered by the creature, the grief of which in turn strikes his father dead. Following a brief spell in an insane asylum, Victor swears vengeance and pursues his creation halfway across the globe before falling behind near Walton's ice-bound ship.
His tale told, Frankenstein dies cursing the creature, who is discovered thereafter grieving over the body of his maker and regretting, though not repenting of, his own monstrous actions. Determined to cremate himself and prevent the secrets of his unnatural creation being deciphered, he vanishes into the northern wastes.