In June 1816, Mary Godwin was eighteen years old and living in a rented villa on the shores of Lake Geneva with Percy Bysshe Shelley, Lord Byron, Byron’s physician John Polidori, and Byron’s companion Claire Clairmont. The weather was catastrophically bad — cold, dark, and rainy throughout a summer that should have been Mediterranean. They were indoors most of the time, reading German ghost stories aloud and eventually agreeing on a competition: each of them would write a supernatural tale.