Robert Langdon, Harvard professor of symbology and religious iconology, arrives at the Guggenheim Museum Bilbao to attend the unveiling of a discovery that "will change the face of science forever". The evening's host is his friend and former student, Edmond Kirsch, a forty-year-old tech magnate whose dazzling inventions and audacious predictions have made him a controversial figure around the world. But the meticulously orchestrated evening suddenly erupts into chaos. Langdon is forced into a desperate bid to escape Bilbao. With him is Ambra Vidal, the elegant museum director who worked with Kirsch to stage the provocative event. Together they flee to Barcelona on a perilous quest to locate a cryptic password that will unlock Kirsch's secret. Navigating the dark corridors of hidden history and extreme religion, Langdon and Vidal must evade a tormented enemy whose all-knowing power seems to emanate from Spain's Royal Palace itself.