Hearthstone: Heroes of Warcraft is getting another wave of new content.

Blackrock Mountain: A Hearthstone Adventure adds 31 new cards to Blizzard’s popular digital game — and the potential for the publisher to further boost the online revenue it’s already making in the nearly $30 billion mobile game market. Players can unlock the new cards by beating computer-controlled bosses and class challenges, similar to the Curse of Naxxaramas adventure. Both are based on raids (dungeons that require cooperation from a large group of players) found in Blizzard’s popular online game, World of Warcraft.

The content slowly rolls out over five weekly released wings. Access to each costs 500 in-game gold or $7. The first wing opens some time next month.

Hearthstone is available on PC, Mac, iOS, and Android. Its first major expansion, Goblins vs. Gnomes, came out in December. Unlike the adventures Curse of Naxxramas and the upcoming Blackrock Mountain, Goblins vs. Gnomes focused specifically on adding new cards (121, to be exact).