Penniless and disgraced, Adelaide Wentworth is feeling rather desperate. With nothing left to lose, she and her sister, Louisa, flee to Lake Geneva with Adelaide's lover, the infamous poet Julian Estes. There, Louisa hopes to persuade Bayard Sonnier—celebrated writer and her former lover—to advance Julian's career. He is their last hope for salvation.

At the Villa Diodati—the place that inspired the writing of Frankenstein sixty years earlier—Louisa plots to rekindle her affair with Bayard, while Adelaide hopes to restore her fading love for Julian by being the muse he needs.

But soon, secrets are revealed, passions ignited, and hidden talents discovered. Adelaide begins to imagine a different life. Confused, she turns to Giovanni Calina—Bayard's assistant and a man with his own secrets and deep resentments—and the two form a dangerous alliance. No one leaves unscathed in this richly imagined, emotionally nuanced tale of passion, ambition, inspiration, and redemption.