The iOS game is marked down from its regular price of $3.99, which is what the Android version is still selling for. Asked how long the App Store deal will be available, Ustwo producer Dan Gray told Polygon that it's a "temporary price drop that we wanted to do just before Christmas." In other words, you should probably snatch up President Frank Underwood's favorite indie game as soon as you can.
For more on Monument Valley, read our review. If you're already a fan of the game, you may want to check out the new officially licensed merch that iam8bit is selling, including Ida, Totem and Crow plushies.
Update: The sale ends at midnight tonight, Ustwo announced on Twitter — that is, whenever the clock strikes midnight in your time zone and the date becomes Dec. 9.