The Mystical Door is free to download, and the free part is complete: you can play the first book from its first page to its last. There's no timer and there are no adverts.

Free

  • The Ranger
  • The Cartographer's Oath, the first book
  • The Training Grounds, an optional practice run that teaches how battles work

The full game is a single one-time purchase, not a subscription. It adds:

  • The Warrior and the Mage, with their own abilities and gear
  • A Study in Fog
  • The Vault of Embers
  • A fourth book, which appears on the library shelf once one hero has finished the other three

The game shows the price before you buy, in your own currency, exactly as Google Play quotes it. Everything you've already played carries over as you left it.

See Buying the full game for how to buy it.