The Lost Symbol - Dan Brown

Harvard symbologist Robert Langdon is summoned to Washington, D.C., to give a last-minute lecture at the U.S. Capitol. But what starts as a routine event quickly turns into a deadly mystery when Langdon finds out that his mentor and friend, Peter Solomon, a prominent Mason, has been kidnapped.

The kidnapper, a tattooed and mysterious man named Mal'akh, demands that Langdon uncover the ancient secrets of the Freemasonssecrets he believes will give him immense power. Mal'akh leaves a severed hand (Peter's) in the Capitol Rotunda as a symbolic clue, initiating a race against time.

Langdon teams up with Peter's sister, Katherine Solomon, a scientist exploring the link between science and spirituality. Together, they unravel a series of Masonic symbols, codes, and puzzles hidden throughout Washington, D.C., in places like the Capitol, the Washington Monument, and the Library of Congress.

As the mystery deepens, Langdon learns the truth about Mal'akhs identity and motivations, which are more personal and twisted than initially believed. Ultimately, the real "lost symbol" is not an object, but an ancient wisdom encoded in the human mindemphasizing the power of thought, belief, and enlightenment.