The episode traces the manuscript's discovery in 1912 by Wilfrid Voynich and its subsequent analysis, which confirms it was created in early 15th-century Europe on vellum with original ink, ruling out modern hoaxes. The hosts describe its sections—botanical, astronomical, biological, and pharmaceutical—and note that the script, Voynichese, follows linguistic patterns yet remains undeciphered despite efforts by cryptographers, the U.S. military, and AI. Theories range from a medieval medical text to a time traveler's guide, but the lack of profit suggests it wasn't a hoax. The hosts consider why people default to explanations like aliens or lost civilizations, and one suggests it might be an unsolvable mystery, perhaps a creative project by a homeschooled child. The episode concludes that some mysteries may be meant to stay unsolved.