The Viking Quest is a game within the game that allows players to spin the new Viking Slots with their coins instead of spins and earn astronomical rewards including a Gold Card!
During the event, there are 10 unique Missions to beat and each one rewards the player with greater and greater rewards that culminate in a Gold Card! When playing the Viking Slots, the Mission can be seen above the Spin button.
All Coins won in the Viking Slots are Raid Protected for 3 minutes after each press of the Viking "Spin" button.
For more information about Viking Quest missions and rewards, please refer to this Article.