Inside the set, you'll find:
- 20 all-new Gambit cards – designed for Arena Mortis but usable in ANY of your games
- 20 all-new Upgrade cards – also usable in ordinary games of Warhammer Underworlds
- A double-sided game board to play on, compatible with all existing Warhammer Underworlds boards
- Tokens and Cards for keeping track of the game
- Updated cards for the Restless Dead gambit and the Sepulchral Warden, reprinted for your convenience incorporating the latest rules updates

This is a supplement. Full gameplay requires the Warhammer Underworlds Beastgrave core rules.