In this sixth installment of the Robert Langdon series, Harvard symbologist Robert Langdon travels to Prague to accompany his romantic partner, prominent noetic scientist Katherine Solomon, to a groundbreaking lecture. Chaos erupts when a brutal murder takes place, and Katherine vanishes along with her explosive manuscript containing discoveries about human consciousness. Targeted by a shadowy organization and hunted by an assassin rooted in Prague's ancient mythology, Langdon must race through Prague, London, and New York to crack cryptic clues and uncover a truth that could change humanity's understanding of the mind forever.