Book of Mercenaries: Guff Runetotem - Druid
It's a new chapter in the Book of Mercenaries, with Guff Runetotem, the Druid. This next chapter is now LIVE! The reward for completing the chapter is 1 pack containing only Druid cards from Standard.
Quote from Blizzard
Book of Mercenaries Guff – Coming June 15
Guff Runetotem has always just wanted to help, but when "helping" means accidentally starting a treant rampage that nearly flattens Thunder Bluff, Guff vows to set things right. His quest for redemption leads him and his companions to the Wailing Caverns. What Guff finds inside will be revealed in Book of Mercenaries Guff, launching June 15th. Defeating all 8 bosses in this linear adventure will reward 1 Druid pack, containing only Druid cards from Standard!