What royal decree does Antigone reveal to Ismene in the opening scene?

Antigone tells Ismene that Creon, the king and their uncle, has just decreed that their brother Polyneices will not be buried. This was a terrible punishment because they believed that a soul whose dead body was left unburied was doomed to roam the earth in limbo, never able to go on to its afterlife. Creon also decreed that anyone who disobeyed his order would be stoned to death. Antigone is angered by this because she loves her brother and wants to give peace to his soul.

Antigone reveals King Creon's decree that their brother Polynices will not be buried. Instead he will be left rot. Their other brother Eteocles will be buried with honour. Antigone, of course, cannot accept this.