An old, mysterious book, a brewer from the 13th century – and the door to the cosmos of the Middle Ages swings wide open. Niklas von Hahnfurt embarks on the rocky path to becoming the best brewer of his time. From his Franconian homeland, he travels through the Weihenstephan monastery to St. Gallen, the stronghold of medieval brewing art. When several pilgrims are murdered with poisoned beer there, Niklas becomes the target of the fanatical inquisitor Bernard von Dauerling. A life-and-death hunt begins. Niklas' escape takes him to the beer cities of Regensburg, Bitburg, and Cologne, and even to Lübeck and London the beer wizard goes. But in the end, a final beer duel with his arch-enemy is inevitable.