Victor Frankenstein's attempt to track down and destroy his satanic creation takes him to the arctic region where, at the point of collapse, he is rescued from the ice-bound seas by Captain Walton. When sufficiently recovered Victor tells the tale of how he came to be in these inhospitable regions. The Captain, whose boat is bound for the North Pole, listens avidly to Victor's tale and retails it in a series of letters intended for his sister.
Victor's narrative enlightens us as to how and why he decided to experiment with the creation of life. Whereas Prometheus stole the sacred fire of Heaven to achieve his purposes, Victor uses galvanism to achieve his dream of "infusing life into an inanimate body". Once he achieves his dream, however, he feels not elated, but soul-sick. The sight of his malformed giant fills him with "breathless horror and disgust".
Finding himself abandoned and rejected, the creature embarks on a savage revenge against his creator. The first victim is Frankenstein's younger brother, William, whose death is soon followed by that of Justine, a family friend, who is wrongfully sentenced for William's murder. Victor suspects that his creature is guilty of the murder, but it isn't until he comes face-to-face with him that he learns why the creature is revenging himself.
In taking over the narrative from Victor, the creature describes the torment and misery of his existence and the deeper yearnings of his soul. His desperate loneliness and need for human affection had led him to the folly of trying to befriend a human family (the De Lacey's). Nevertheless, it was by eavesdropping on this particular family over an extent of time that the creature educated himself in language, literature and history. On reading Milton's Paradise Lost, the creature discovered in Satan a heroic inspiration for his own revenge. Yet he would stop any further acts of attrition if, as he tells Victor, he had a female companion of his own species to relieve his loneliness.
Victor is not entirely unmoved by the creature's plea for a partner and initially agrees to produce one. To fulfil his task he journeys to England and then Scotland in the company of Clerval. On their arrival in Edinburgh, the two friends decide to part. Clerval will stay put, leaving Victor to travel alone to the Orkneys, where he hopes to settle to his work.
The creature, meanwhile, has been shadowing his creator to ensure that he honors his promise. But the promise is unfulfilled. Victor's nerve fails him after contemplating the monstrous offspring, which might result from his creation of a female creature. He abandons his work halfway. The hopeful creature arrives on his doorstep only to witness the destruction of his intended partner and in his anguish he threatens revenge himself at some future date.
Victor takes leave of the Orkneys in a skiff with the intention of returning to the Scottish mainland and visiting Clerval in Edinburgh before journeying back home to Geneva. But having fallen asleep in his skiff he drifts to the Irish coast instead. His greatest shock on arriving in Ireland is to be accused of murdering Clerval whose body has just been washed up on the shore. It is three months before the jailed Victor is tried, acquitted and freed to return home.
Once back in Geneva, Victor decides at last to marry Elizabeth, the woman he has long promised to marry. The marriage is a quiet affair, but overshadowed for Victor by the vow that the creature made at the end of their last meeting: "I shall be with you on your wedding night". It is while Victor is searching the passages of the inn at which he and Elizabeth are staying that the creature claims his final victim.
Stunned by the death of Elizabeth, Victor now reverses the roles of the pursuer and the pursued and sets out to find and destroy the creature. But by the time he meets Captain Walton, the rigors and privations of his pursuit have greatly enfeebled him. Although he recovers sufficiently to tell his story, it seems the effort of telling it has destroyed him. He passes away peacefully in his cabin unaware that the creature has stolen aboard to look at him in the composure of his death. When Captain Walton discovers him in the cabin, the creature expresses a sense of remorse for his crimes and then vanishes to create his own funeral pyre. The Captain, meanwhile, has decided not to risk the lives of his own crew on his intended voyage to the pole and now that the ice has melted, he is set to return home.