It is 1666, one year after plague has devastated England. Young widow Cecilia Thorowgood is a prisoner, trapped and isolated within her older sister's cavernous London townhouse. At the mercy of a legion of doctors trying to cure her grief with their impatient scalpels, Cecilia shows no sign of improvement. Soon, her sister makes a decision born of desperation: She hires a new physician, someone known for more unusual methods. But he is a foreigner. A Jew. And despite his attempts to save Cecilia, he knows he cannot quell the storm of sorrow that rages inside her. There is no easy cure for melancholy.

David Mendes fled Portugal to seek a new life in London, where he could practice his faith openly and leave the past behind. Still reeling from the loss of his beloved friend and struggling with his religion and his past, David is free and safe in this foreign land but incapable of happiness. The security he has found in London threatens to disappear when he meets Cecilia, and he finds himself torn between his duty to medicine and the beating of his own heart. He is the only one who can see her pain; the glimmers of light she emits, even in her gloom, are enough to make him believe once more in love.

Facing seemingly insurmountable challenges, David and Cecilia must endure prejudice, heartbreak, and calamity before they can be together. The Great Fire is coming--and with the city in flames around them, love has never felt so impossible.