Brown gives them a hectic but pretty straightforward plot played out within a few kilometres of the Capitol in Washington during 24 hours.
The story goes something like this. Robert Langdon – familiar to readers of The Da Vinci Code – arrives in Washington by private jet. He has come at the invitation of his friend and mentor Peter Solomon. Solomon, apart from being a multibillionaire scholar and sage, is Washington's highest- ranking Mason and also the director of the prestigious Smithsonian Institute. Almost straight away, Langdon discovers that he is the victim of a ruse. Instead of meeting Solomon, he stumbles on Solomon's severed right hand, its fingertips tattooed with mystic symbols, pointing up at the vast dome of the Capitol. There follows 500 pages of a breathless search for a) Solomon and b) the secret his tormentor is trying to extract from him.
That secret seems to be of such earth-shattering significance that the CIA is on the scene almost immediately, in the person of Inoue Sato, the chain-smoking, cadaverous Japanese-American chief of the CIA's Office of Security.
Solomon's sister, Katherine, also gets involved in the mayhem. She is a top-notch researcher in noetic science. Katherine has been able to verify the central hypothesis of noetic science – that thoughts and feelings, indeed the soul itself, are material objects with quantifiable mass. So thoughts, especially thoughts acting in concert, can exert physical influence – mind over matter, in a way.
All this, and much more besides, gets mixed up with Freemasonry, with the founders of America and the great monuments of Washington, DC, with Isaac Newton and Albert Einstein and with a horribly disfigured, be-tattooed villain calling himself Mal'akh (the name inspired by Moloch in Milton's Paradise Lost), who has a particular grudge against the Solomon family. And also an unquenchable thirst to get his hands on the great secret concealed beneath a secret Masonic portal somewhere in Washington.
How will Langdon extract himself from the coffin-like box in which he has been confined? How will Katherine elude her assailant in a pitch-black airtight hangar the size of several football fields? What lies behind the concealed door in a sumptuous mansion in the poshest part of Washington?