Langdon hurries through Prague toward the Klementinum’s astronomical tower, scanning the thin crowd for any sign of Katherine and pushing onward in the cold wind.

Passing the Mozart Prague hotel, Langdon remembers the city’s Signal Festival, when landmark facades become canvases for light projection and video mapping, and he reflects on Prague’s taste for avant-garde art.

In a small park, Langdon’s attention is caught by an advertising kiosk with a poster for the computer game HALO. The word hits him as a sharply timed coincidence, and he wonders whether it is an omen connected to Katherine, given their recent conversation.

Langdon recalls Katherine’s argument that halos have been misunderstood: the rays represent consciousness flowing in—not out—and “enlightenment” means having a better receiver. Langdon mentally connects this to biblical descriptions of prophecy as receiving divine wisdom, and he considers how older halo traditions in other religions once showed rays that Christianity later reduced to a simple disk.

Katherine had pressed the idea further by linking it to memory, suggesting the brain is too small to store a lifetime of vivid images and instead accesses information like “cloud computing.” She teases Langdon about his hesitation to fully accept the theory, and he presses her to reveal her discoveries—only for Katherine to insist he will have to wait for her book.