Summer 1816: London is a hostile place for the newly disembarked Mehrunissa Begum, who’s come to deliver her brother’s letter of inheritance before returning to her comfortable life in Lucknow, India. Only, she can’t find her brother anywhere and has no money for the return trip. With nowhere else to go, Mehr finds refuge in a boardinghouse for Indian maids. If she can’t find her brother, she reasons, she will get a job and start saving.

Mehr is soon hired at the English estate of Mary and Percy Shelley, young artists of burgeoning fame who are on the run from secrets of their own. Mary is brooding and quiet, but takes a curious liking to her new maid, asking her to accompany the Shelleys and her stepsister, Claire—as well as the eccentric Lord Byron and his physician, John Polidori—to Lake Geneva for the summer.

Almost immediately, Mehr notices strange, ghostly events at the villa. The walls breathe, portraits shift, and phantoms appear like unbidden guests who refuse to leave. The weather is fierce and foreboding, showing no signs of softening its relentless pall. And as Mary Shelley begins work on what will become her earth-shattering literary phenomenon, Mehr finds herself trapped in the villa as the rest of its inhabitants descend into madness.