Book of the Priestess Bonus Buy Slot by Evoplay

The 87x buy bonus drops you straight into 10 free spins with one randomly chosen expanding symbol already active and the Ancient Mask counter running from spin one. That counter is what makes the bonus round escalate. Every Book symbol (the game's combined Wild and Scatter) that lands during free spins ticks the mask down by one notch, starting at 7. Reach zero, and the game selects a second expanding symbol from the remaining pool, adds 5 extra spins, then resets the counter. The cycle repeats - a third expand at the next zero, a fourth after that, all the way up to 9 if the round lasts long enough.

Expanding symbols stretch to fill all three rows on whichever reel they land. They also pay across non-adjacent reels, which is unusual for a book-style game and matters more as you stack expanders. Two or three expanding symbols landing on the same spin each expand and pay in sequence. The base version plays identically but without the buy-in option, so this edition is purely a shortcut past base game grinding. No mechanical differences once you're inside the feature.

The Priestess portrait at 500x for five sits well above everything else on the paytable - the next symbol drops to 200x, then a steep fall to 75x and below. Which symbol gets selected as the first expander shapes the round. Golden Mayan pillars carved with eye motifs stand on both sides of the reels against dark cracked stone, and the background opens into dense tropical jungle with a step pyramid just visible through the canopy. The card royals are cast in a bronze-amber stone texture that blends into the temple walls, while both character portraits - the Priestess in her red-feathered headdress and the warrior in green plumage - pop against the dark reel backdrop.