Set at the end of the 18th century, Frankenstein is told in the first person by three different narrators: the explorer Robert Walton, scientist Victor Frankenstein, and the unnamed Monster. The book is written in the form of letters from Walton to his sister back in England, re-telling events told to him after rescuing Frankenstein in the Arctic.
By using the device of a letter-writing narrator, Mary Shelley gives the book a sense of realism that helps the audience to imagine that these fantastical events really occurred.
Robert Walton tells of both his family history and hopes for the highly dangerous expedition he has embarked upon. He meets Victor Frankenstein shortly after seeing a creature 'of gigantic stature' on an ice raft speed away from his ship, which has become trapped in ice somewhere in the Arctic.
Victor is very ill and is looked after by Walton, who has complained in his letters of not having a companion to share his feelings. As the two become friends, Victor begins his tale; one he hopes will be a warning to Walton about the dangers of ambition and the pursuit of knowledge. Walton says he will write down everything his friend tells him.