Zeno, an illegitimate son, is adopted by the Ligre household, a rich banking family of Bruges. Zeno renounces a comfortable career in the priesthood and leaves home to find truth at the age of 20. In his youth, after leaving Bruges, he greedily seeks knowledge by roaming the roads of Europe and beyond, leaving in his wake a nearly legendary — but also dangerous — reputation of genius due to his scientific accomplishments — as well as the ire of the Christian authorities for his atheistic attitudes. Zeno's travels take him from his native Bruges as far away as the court of
Gustav Vasa, whose ill-fated son
Erik he tutors and attempts to admonish, to the
Louvre of
Queen Catherine where he encounters the poisoner
Cosimo Ruggeri, and also to the lands of the
Ottoman Empire, for whose navy he designs a rudimentary flamethrower. Meanwhile, Zeno's mother Hilzonda becomes involved with the
Anabaptist movement and is witness to the
Münster rebellion and its suppression by forces under
Bishop Waldeck. She dies in Münster. Zeno's cousin, Henry Maximillian, follows a different path. As a young man, he volunteers into the armies of the
Kingdom of France and seeks a romantic life of adventure. He passes a lifetime as a soldier and survives many engagements including the fearsome
Battle of Ceresole, during which he is felled by an
arquebus bullet and very nearly dies. He later describes to Zeno the "
black hole" he glimpsed at Ceresole before he was revived. Years later, Henry Maximillian is killed suddenly in an ambush by the
Imperial army during the
Siege of Siena. His book of poetry is buried with him in a shallow grave, and he leaves behind only an inscription carved into the rim of the
Fontebranda in honor of the aristocratic Signora Piccolomini who he loved. Eventually returning to Bruges under an assumed name, Zeno confides only in his friend and fellow atheist Jan Myers. When his young assistant Cyprian is caught in an illicit
Adamite cult, Zeno's true identity is exposed and he is condemned to be
burned at the stake for, among other things, the crime of atheism. Before he can be burned, Zeno kills himself in prison by severing his veins with a smuggled razor. ==Themes==