A singleplayer campaign called Curse of Naxxramas is coming to Hearthstone: Heroes of Warcraft, Blizzard has announced.

The inspiration for the adventure is Naxxramas, a dungeon in World of Warcraft that is the floating necropolis for the powerful archlich Kel’Thuzad. It has five wings, each with bosses that have unique cards and hero abilities.

The expansion adds 30 new cards to the game that are earned by defeating these bosses, with completion of each wing guaranteeing the player a new Legendary class card.

Curse of Naxxramas has its own unique game board, as well as nine class challenges that force players to duel using a predetermined deck. According to Blizzard, the challenges put a difficult twist on existing encounters within the adventure, but reward players with new class-specific cards.

The expansion will be available over a five week period, with the first wing, The Arachnid Quarter, free for all players. Other wings must be bought with in-game gold or real money. As each is released, the cards available therein will show up in Arena mode, even if they haven't yet been earned.

“Players will battle against bosses in this single-player mode that will test their ability to build decks, adapt strategies, and conquer the creepiest of villains,” said the company.

It is not yet known which platforms Curse of Naxxramas is coming to, but PC first is a safe assumption.

Blizzard said it will be available "soon".