Note: This are not official information and may be wrong.
- Tombs of Terror is Hearthstone newest Adventure that will be released September 17 at 7 pm (CEST). Note: Releaseday confirmed (Source)
- The Adventure will cost $19.99
- For pre-purchase you will be rewarded a random Saviors of Uldum legendary and a special card back
We see, in this Screenshot, one minute before the possible release it says “Opens in 1 week”
This screenshot was taken with the likely release, we see it is missing now in the menu. The Thumbnail was also taken at this time, and you see it seems to be playable.
This is the cardback you will get, this one is viewable for everyone.