What events that led up to her idea for the plot of Frankenstein?

Mary Shelley conceived the plot of "Frankenstein" during the summer of 1816, often referred to as the "Year Without a Summer," when volcanic activity led to unseasonably cold weather. While staying at the Villa Diodati in Switzerland with Lord Byron, Percy Bysshe Shelley, and others, they engaged in a ghost story competition. This inspired Shelley to explore themes of creation and responsibility, drawing from her own experiences with loss and the scientific advancements of her time, particularly in electricity and galvanism. These elements coalesced into her groundbreaking novel about the consequences of playing God.