The next Hearthstone Adventure is The League of Explorers, and its first wing releases this week.

As Blizzard Entertainment revealed at BlizzCon over the weekend, The League of Explorers sends brave duelists far and wide on harrowing expeditions to recover a mysterious lost relic. It will pit them against dastardly villains in fierce encounters that will require unique strategies to conquer. And yes, there might be serpents.

It introduces four intrepid adventurers – Elise Starseeker, Reno Jackson, Sir Finley Mrrgglton, and Brann Bronzebeard – who will navigate through the Temple of Orsis, Uldaman, the Ruined City, and the Hall of Explorers in hopes of discovering lost artifacts that will lead them closer to the relic. A fourth wing will take place at Hall of Explorers in the Ironforge.

The expansion will add a total of 45 cards to the game, and you can see 'em all here.

Features, as per the official site:

New Cards: The League of Explorers contains 4 wings packed with fiendish bosses, puzzling traps, and ancient mysteries for you to discover. When you overcome a boss or an encounter for the first time, you will earn brand-new cards for your collection!
Legendary: When you defeat all the challenges in a wing for the first time, you will be rewarded with that wing’s legendary card – for example, Elise Starseeker!
League of Explorers
Class Challenges: The League of Explorers also includes nine all-new class challenges that task you with using a special pre-built deck to prove your skill. Succeed, and the new class cards are yours.
New Game Boards: Immerse yourself in the adventure with all-new playing fields!
Meet the League: Make friends with renowned explorer and fearless dwarven historian Brann Bronzebeard and the other members of the League of Explorers: dashing treasure hunter extraordinaire Reno Jackson, brilliant night elf scholar Elise Starseeker, and gentleman (gentle-fish?) murloc adventurer Sir Finley Mrrgglton!
New Keyword: The League of Explorers introduces a new keyword that lets you do some digging of your own: Discover! You’ll treasure the opportunity to dig up cards and select the one you need the most!
Heroic Mode: If you’re ready for a challenge, you can try taking on the Heroic Mode version of any mission that you’ve cleared. This extra-tough game mode is designed for players eager to test their puzzle-solving skills against incredibly powerful opponents. Bring your best deck and your sharp wits.

League of Explorers is a fun mix of memorable locations from Warcraft and exciting new locations to battle through,” said Blizzard CEO Mike Morhaime.

“Players who join the expedition are in for a good time and will walk away with some great new cards for their collections.”

The first wing will be released on November 13 on Windows and Mac PCs, iOS, and Android.

The four League of Explorers locations will open on a weekly basis over the course of a month, with a one-week break in the middle during the Thanksgiving holiday.

The League of Explorers can be purchased in full for US$20, one location at a time for 700 gold or US$7 each, or in discounted bundles based on the number of individual locations already purchased.