The League of Explorers is Hearthstone's third adventure. The adventure contains 4 wings, with 13 boss encounters, as well as a Heroic mode and 9 Class Challenges. In addition to the usual boss battles, the adventure also debuts a new kind of encounter - where the player must survive through several rounds of traps, ambushes and environmental events to escape to safety. The adventure adds 45 new collectible cards, as well as new card backs and 2 new battlefields. The League of Explorers sees the player following four famed adventurers - Elise Starseeker, Reno Jackson, Sir Finley Mrrgglton, and Brann Bronzebeard - on a journey through some of Azeroth's most exotic and dangerous locations, on a quest to recover an ancient Titan artifact - the Staff of Origination. As each wing is completed, players gather pieces of the Staff, and put them on display in the museum. However, the League of Explorers are not the only ones searching for the artifact, and danger waits within the shadows.