The Lost Symbol is the third installment in Dan Brown's Robert Langdon series. This conspiracy mystery takes place in Washington, D.C., where Langdon is summoned to unlock the secrets of the Freemasons and locate a hidden ancient portal. As he races against time, Langdon must decipher cryptic symbols and navigate through hidden chambers, all while being pursued by a ruthless adversary. The Lost Symbol is a thrilling blend of history, symbolism, and suspense that will keep you hooked from start to finish.