A feast of "vampires" and a killing game.
All participants have committed heinous crimes. The winner will wash away all charges and realize any wish; the loser will sacrifice his life for his failure and turn into a handful of loess.
However, these people will either end their lives with a bullet, or they will be trapped in that square sky and lose their freedom, or they will run away and never see their loved ones again. In the end, they will end up with the above two endings or die alone.
This seems to be a desperate gamble, but in fact it is their only hope for a new life, and it is their last struggle before death.