Harvard professor Robert Langdon is summoned to deliver an evening lecture in the Capitol Building, Washington DC. But within minutes of his arrival, a gruesome and disturbing discovery is made at the epicentre of the Rotunda. Langdon recognizes it as an ancient invitation, beckoning its recipient towards a long-lost world of hidden wisdom. And when Langdon's revered mentor is brutally kidnapped, he realizes his only chance to save his old friend is to accept this sinister summons... All that was familiar is transformed into a shadowy, clandestine world in which Masonic secrets and never-before-seen revelations seem to be leading him to a single impossible and inconceivable truth. As Langdon will discover, there is nothing more extraordinary or shocking than the secret which hides in plain sight...