The novel follows a boy from the Spessart named Simplicius in the Holy Roman Empire during the 30 Years War as he grows up in the depraved environment and joins the armies of both warring sides, switching allegiances several times. Born to an illiterate peasant family, he is separated from his home by foraging dragoons and is eventually adopted by a forest hermit. He is conscripted at a young age into service, and from there embarks on years of foraging, military triumph, wealth, prostitution, disease, travels to Russia, and countless other adventures.