Franciscan friar
William of Baskerville and his novice, Adso of
Melk, arrive at an early 14th-century
Benedictine abbey in Northern Italy. A mysterious death has occurred ahead of an important theological Church conference—a young
illuminator appears to have committed suicide. William confronts the worried Abbot and gains permission to investigate the death. Over the next days, several other bizarre deaths occur. William and Adso make the acquaintance of Salvatore, a hunchback who speaks gibberish in various languages, and his handler and protector, Remigio da Varagine. William deduces from Salvatore's use of the term
"penitenziagite" that he had once been a member of
a heretical sect and infers that Salvatore and Remigio may have been involved in the killings. Meanwhile, Adso encounters a peasant girl who snuck into the abbey to trade sexual favors for food. She seduces him and has sex with him. Investigating, William and Adso deduce that the blackened fingers and tongues of the dead monks are somehow connected with a book that has gone missing, which they endeavour to find before more monks are killed. Keen to head off accusations of the murders being the work of the Devil, the duo discovers and explores a labyrinthine library in the abbey's forbidden principal tower. William finds that it is "one of the greatest libraries in all Christendom," containing dozens of works by Classical masters such as
Aristotle, thought to have been lost for centuries. The library is kept hidden because such advanced knowledge, coming from pagan philosophers, is difficult to reconcile with Christianity. His investigations are curtailed by the arrival of
Bernardo Gui of the
Inquisition, summoned for the conference and keen to prosecute those he deems responsible for the deaths. William and Bernard have clashed in the past, and the zealous inquisitor has no time for theories outside his own. Salvatore and the girl are found fighting over a black cockerel while in the presence of a black cat. Gui presents this as irrefutable proof that they are in league with Satan and tortures Salvatore into a
false confession. Salvatore, Remigio, and the girl are dragged before a tribunal, where Gui intimidates the Abbot into concurring with his judgment of heresy. But William, also "invited" by Gui to serve on the panel of judges, refuses to confirm the accusations of murder, pointing out that the murderer could read Greek, a skill that Remigio does not possess. Gui resorts to extracting a confession from Remigio by the threat of torture, and clearly plans to take care of William for good. When the head Librarian succumbs like the others, William and Adso ascend the forbidden library, and come face to face with the Venerable Jorge, one of the oldest monks in the abbey, with the book they have been searching for. William deduces that the book is the only remaining copy of Aristotle's
Second Book of Poetics, which describes comedy and how it may be used to teach. Believing laughter and jocularity to be instruments of the Devil, Jorge has poisoned the pages to stop the spread of what he considers dangerous ideas: those reading it would ingest the poison as they licked their fingers to aid in turning pages. Confronted, Jorge throws over a candle, starting a blaze that engulfs the library. William insists that Adso flee, as he collects an inadequate armload of invaluable books to save; the volume of
Poetics, Jorge, and the rest of the library are lost. Meanwhile, Salvatore and Remigio have been burned at the stake. The girl has been slated for the same fate but local peasants take advantage of the chaos of the library fire to free her and turn on Gui. Gui attempts to flee but they throw his wagon off a cliff, to his death. William and Adso later take their leave of the Abbey. On the road, Adso is stopped by the girl, silently appealing for him to stay with her, but Adso continues on with William. Years later, a much older Adso reflects that he never regretted his decision, as he learned many more things from William. Adso also states that the girl was the only earthly love of his life, yet he never even learned her name. ==Cast==