The novel takes place in 16th-century Central Europe (mostly in Flanders), split by religious conflict and shaken by wars. The protagonist is Zeno Ligr, an alchemist, physician, and naturalist. The original title of the novel - Black Stage (or Blackening Stage) - the name of the first and most difficult stage of the alchemical process - the Great Doing The essence of the Black Stage is the "division and decomposition of the substance" to a state of some amorphous "black mass" of the primary elements, in which, as in the original chaos, all the potentialities are hidden. According to the author, the Black Stage also symbolically denotes the spirit's attempts to escape from the captivity of habitual notions, routines and prejudices. Zeno goes through his "black stage" against the backdrop of the horrors of Europe's era of religious wars Most of the characters in the novel die a painful death, often describing the atrocities and methods of execution adopted at that time. A kind of inserted novel in the novel vividly and rigidly depicts the activities of Jan Leidensky and his henchmen, the tragedy of Munster, who fell victim to the madness of fanatics, and the bloody finale of the Anabaptist sect.