On August 3, 1797, Mary Wollstonecroft Godwin is born to William Godwin and Mary Wollstonecraft in London, England. After the death of her mother from puerperal fever shortly after giving birth, Mary was raised by her father alongside her half-sister Frances Imlay. William Godwin provided Mary with a broad education through tutoring her himself as well as providing her with access to his own library and to the numerous intellectuals who visited him. Mary eventually met poet Percy Bysshe Shelley, who was estranged from his wife at the time, and the two began an affair. In 1814, the couple, accompanied by Mary's half-sister Claire Clairmont (Mary's father had remarried a few years after her mother's death), ran away to France. The trio eventually returned home after running out of money. The next few years saw Mary facing ostracism from her father (who had been upset that she had run away and had an affair with a married man), the lost of a child born prematurely to her and Shelley, and Shelley's own affair with her stepsister.

In 1816, the trio plus Mary's second child (a boy named William) ventured to Lake Geneva in Switzerland to spend time with Lord Byron. While there, a challenged was issued among the group to create their own ghost stories following a discussion and retelling of German ghost stories. Out of this Mary Godwin, now referring to herself as Mary Shelley, wrote a short story which would then become her novel Frankenstein; or the Modern Prometheus in which a scientist sought to defy death itself.

In 1816, Percy Bysshe Shelley's estranged wife Harriet committed suicide. Shortly thereafter, Mary and Percy married and Percy was granted custody of his two children by his first wife. Mary also gave birth to a daughter, Clara. However, both children would pass away during the next two years, devastating the couple. In 1819, Mary gave birth to her fourth child, Percy Florence Shelley. In 1822, her husband drowned when his boat sank in the Gulf of La Spezia off the northwestern coast of Italy during a severe storm. Mary, despite financial difficulties, continued to pursue her career as an author and raise her sole surviving son on her own, refusing to surrender custody to her father-in-law.

On February 1, 1851, Mary Shelley passed away at the age of fifty-three.