Frankenstein is written in the form of a frame story that starts with Captain Robert Walton writing letters to his sister. It takes place during an unspecified time in the 18th Century, as the letters' dates are shown as "17—".
Captain Walton's introductory frame narrative
The novel Frankenstein is written in epistolary form, documenting a correspondence between Captain Robert Walton and his sister, Margaret Walton Saville. Walton is a failed writer who sets out to explore the North Pole and expand his scientific knowledge in hopes of achieving fame. During the voyage the crew spots a dog sled mastered by a gigantic figure. A few hours later, the crew rescues a nearly frozen and emaciated man named Victor Frankenstein. Frankenstein has been in pursuit of the gigantic man observed by Walton's crew. Frankenstein starts to recover from his exertion; he sees in Walton the same over-ambitiousness and recounts a story of his life's miseries to Walton as a warning.
Victor Frankenstein's narrative
Victor begins by telling of his childhood. Born in Naples, into a wealthy Geneva family, Victor and his brothers, Ernest and William, are encouraged to seek a greater understanding of the world through science. As a young boy, Victor is obsessed with studying outdated theories that focus on simulating natural wonders. When Victor is five years old, his parents adopt an orphan, Elizabeth Lavenza, with whom Victor later falls in love.
Weeks before he leaves for the University of Ingolstadt in Germany, his mother dies of scarlet fever, creating further impetus towards his experiments. At university, he excels at chemistry and other sciences, soon developing a secret technique to impart life to non-living matter, which eventually leads to his creation of the Monster.
Because of the difficulty in replicating the minute parts of the human body, Victor is forced to make the Creature roughly eight feet tall. As a result, the beautiful creation of his dreams is instead hideous, with yellow eyes and skin that barely conceals the muscle tissue and blood vessels underneath. Repulsed by his work, Victor flees. Saddened by the rejection, the Creature disappears.
Victor falls ill from the experience and is nursed back to health by his childhood friend, Henry Clerval. After a four-month recovery, he returns home when he learns of the murder of his brother William. Upon arriving in Geneva, Victor sees the Monster at the crime scene, leading him to believe the Creature is responsible. Justine, William's nanny, is convicted of the crime after William's locket is found in her pocket. Victor doubts anyone would believe his story, which could stop Justine's hanging.
Ravaged by grief and guilt, Victor retreats into the mountains. The Monster locates him, pleading for Victor to hear his tale. Intelligent and articulate, the Creature says that his encounters with people led to his fear of them, driving him into the wilderness. While living near a cottage, he grew fond of the family living there. The Creature learned to speak by listening to them and he taught himself to read after discovering a lost satchel of books. When he saw his reflection in a pool, he realized his physical appearance was hideous. Despite this, he approached the family in hopes of becoming their friend, but they were frightened and fled their home. The Creature then burned the cottage in a fit of rage, and murdered Victor's brother, Will.
The Monster demands that Victor create a female companion like himself. He argues that as a living being, he has a right to happiness. The Creature promises he and his mate will vanish into the South American wilderness, never to reappear, if Victor grants his request.
Fearing for his family, Victor reluctantly agrees. Clerval accompanies him to England, but they separate in Scotland. Victor suspects that the Monster is following him. Working on the female creature on the Orkney Islands, he is plagued by premonitions of disaster, particularly the idea that creating a mate for the Creature might lead to the breeding of a race that could plague mankind. He destroys the female creature after he sees the Monster watching through a window. The Monster confronts him, vowing to be with Victor and Elizabeth on their upcoming wedding night. The Monster then kills Clerval, leaving the corpse to be found where Victor lands in Ireland. Victor is imprisoned for Clerval's murder and suffers another mental breakdown in prison. After being acquitted, he returns home with his father.
In Geneva, Victor is about to marry Elizabeth and prepares to fight the Monster. Wrongly believing the Creature threatened his life, the night before their wedding Victor asks Elizabeth to stay in her room while he looks for "the fiend". While Victor searches the house and grounds, the Creature murders Elizabeth. From the window, Victor sees the Monster, who taunts Victor with Elizabeth's corpse. Grief-stricken by the deaths of William, Justine, Clerval, and Elizabeth, Victor's father dies. Seeking revenge, Victor pursues the Monster to the North Pole, but he does not kill his creation.
Captain Walton's concluding frame narrative
At the end of Victor's narrative, Captain Walton resumes the telling of the story. A few days after the creature vanishes, the ship becomes entombed in ice and Walton's crew insists on returning south once they are freed. In spite of a passionate speech from Frankenstein, encouraging the crew to push further north, Walton realizes that he must relent to his men's demands and agrees to head for home. Frankenstein dies shortly thereafter.
Walton discovers the creature on his ship, mourning over Frankenstein's body. Walton hears the creature's misguided reasons for his vengeance and expressions of remorse. Frankenstein's death has not brought him peace. Rather, his crimes have increased his misery and alienation, and his words are almost exactly identical to Victor's own in describing himself. He vows to kill himself on his own funeral pyre so that no others will ever know of his existence. Walton watches as he drifts away on an ice raft that is soon lost in darkness, never to be seen again.