Hearthstone Expansion Missions Detailed

Blizzard has revealed details of the eight Knights of the Frozen Throne missions rolling out over the next several weeks.
The first mission set, which is set to go live today but is not, however, live for all players as of publish time, contains the Rise of the Frozen Knights prologue and The Lower Citadel, featuring "three bosses." The reward for completing the first mission set is a legendary card for the prologue and a card pack for the Lower Citadel.
The second mission set, Battle for Icecro