The netherworld opens its dark gates, inviting the brave ones to step in and follow the Ba between the worlds of the dead and the living.  Those who are lucky and find the Secret of Ba will be guided through the darkness of the infernal realm, where immortal riches are guarded by the souls of the dead. Any win on the screen activates the Shatter mode. Win combinations shatter to allow for new symbols to appear in order to form new winning combinations. A maximum count of shatter rounds is 4. A win multiplier increases with each shatter round up to 4. Three Book symbols only trigger 10 re-triggerable Free Spins. At the beginning of Free Spins, a special expanding symbol is selected and it expands to cover the whole reel. Multiple special symbols do not need to appear on neighboring reels to expand. No new special symbol appears when Free spins are retriggered. Free Spins always start with 1x multiplier and it increases up to 4x.