Rudolf II was obsessed. His court at Prague Castle was less a royal household than a laboratory — astronomers, astrologers, and alchemists crowding its halls in pursuit of gold, immortality, and the hidden architecture of the universe.
His chief alchemist, Edward Kelley, claimed he had done it. The formula exists, he wrote in his final letter before imprisonment. I hid it where the city's four elements meet.
You are a researcher at the Czech National Library. A colleague has gone missing. On his desk: a copy of Kelley's letter, and a note in a different hand:
"Don't follow this. They're already watching the bridge."
You follow it anyway. Prague's Old Town Square is where Kelley always began.