The Tree of Knowledge follows the medical education of Andrés Hurtado, his short practice of medicine and his increasing isolation from the profession. Set in 1880s and 1890s Spain, Andrés can see things shrewdly but his desire to remain detached from the world he sees as deeply flawed proves to be an ineffectual way to live. The struggle to answer to which he should adhere—the Tree of Knowledge (science) or the Tree of Life—underlies his decisions and his outcome.