Famed Harvard symbologist Robert Langdon answers an unexpected summons to appear at the U.S. Capitol Building. His planned lecture is interrupted when a disturbing object - artfully encoded with five symbols - is discovered in the building. Langdon recognizes in the find an ancient invitation into a lost world of esoteric, potentially dangerous wisdom. When his mentor Peter Solomon - a longstanding Mason and beloved philanthropist- is kidnapped, Langdon realizes that the only way to save Solomon is to accept the mystical invitation and plunge headlong into a clandestine world of Masonic secrets, hidden history, and one inconceivable truth.