It’s showtime in Karazhan.

The second wing for Hearthstone: Heroes of Warcraft’s latest adventure, One Night in Karazhan, is now live. It gives players new bosses to fight and (more important) new cards to earn. Hearthstone¬†generates approximately $20 million a month from in-game purchases and is the biggest hit in the $1.2 billion digital card game market. New content like this keeps players engaged and more likely to keep spending money.

One Night in Karazhan is based on a raid from the online game World of Warcraft, which took place in a magical tower. It featured fights in an opera house section, which is now represented in this wing of the expansion. The Opera is the second of four wings, each released weekly.