A retired naval officer, rationalist, and skeptic who believes in the progress of science and the "lights" of reason.

The two protagonists are unlikely companions with opposing worldviews:

Their trek from Madrid to Paris is fraught with danger, including:

The novel features a parallel modern-day plot where a narrator (a fictionalized version of Pérez-Reverte) details his own investigation into the historical facts, consulting specialists and bibliophile dealers to piece together the academics' story. Algunos Hombres Buenos Trailer: Unveiling The Drama - Ftp

Back in Madrid, a faction of fellow academics opposed to the Enlightenment hires a mercenary, Pascual Raposo , to follow the pair and sabotage their mission at any cost.