London, 1814: Mary Godwin and her stepsister, Jane Clairmont, possess quick minds bolstered by an unconventional upbringing. Though quieter and more reserved than the boisterous Jane, Mary’s imagination is keen, and she longs for real-world adventures. One evening, an opportunity arrives in the form of a dinner guest. At 21, Percy Bysshe Shelley is already a renowned poet and radical. When Mary comes downstairs in search of a book after the party has broken up, she finds instead a man face down on the floor --- with a knife in his back. The dead man, it seems, was a former classmate of Shelley’s, and lately had become a personal and professional rival. Mary, Jane and Shelley are all drawn to learn the truth behind the tragedy, especially as each discovery seems to hint at a tangled web that includes many in Shelley’s closest circle.