House of Screams is a dungeon that can be found in Westmarch Commons in Diablo III. In the far end of the house, several citizens are trapped with Revelor, starting an unmarked event when the player approaches. Killing the unique Revenant will end it, but until he is defeated, more Revenant Archers and Revenant Soldiers will constantly spawn.
Even if the Nephalem dies, however, Revelor will not kill the peasants. As such, for gameplay purposes, it is not possible to "fail" the event.