How Does Parzival Reach Chthonia in Ready Player One?

In Ready Player One, Parzival (Wade Watts) gets to Chthonia by solving the first gate's riddle and completing the challenge. The riddle was 'What is the only place that copper, wood, iron, and stone can enter, but never leave?' The answer was 'An atom.' This led him to a virtual recreation of the classic video game Joust, where he had to win a game against the Lich King to obtain the Copper Key. The key opened a gate to a planet called Frobozz, where he had to search for a hidden Easter egg in a text adventure game called Zork. Completing Zork gave him the location of the portal to Chthonia, where he found the Jade Key.