Player's Guide Dragon's Maze.

The Guilds of Ravnica are under the spell of a huge puzzle that runs through the metropolis. There are rumors that the person who is the first to crack the puzzle will get earth-shattering power. All ten Guilds are in a race to be the first to solve the mystery. Does your Guild win the ultimate prize?
Dragon's Maze is the third set in the Return to Ravnica Block and consists of 156 cards.

This Magic: the Gathering Player's Guide gives you a glimpse into the world of Dragon's Maze. In addition, the Player's Guide is a complete encyclopedia of all cards from this set.

Note: the description is machine translated and might contain errors.