To begin the Public Quest, enter one of the portals below The Monolith during the second stage of the Contested City event in IC. You will be prompted to leave your instance. Click OK to enter. If you choose to leave out of the portal while inside, you will be ported to The Maw outside of the entrance to IC.
To begin the quest, engage one of the heroes in the center.
Stage 1: Edit
Kill the 8 heroes. They are a relatively easy tank'n'spank. A group, even with limited warding, should have no trouble. There is no timer. When all 8 are down, a portal appears. Click it to port upstairs to the next stage.
Stage 2: Edit
There are 8 stones with three mobs each in front of them. Kill each set of mobs, and interact with the stone behind them afterwards. When all 8 stones have been interacted with, the next stage will begin. There is no timer.
Stage 3: Edit
The lord is up above the landing where the previous stage was. She will do a ranged chain lightning which will one-shot most players without Superior (Invader/Darkpromise) warding. It can be Disrupted, so Hold the Line can mitigate significant damage. A fully warded group should engage her quickly, which will also reduce how much she casts the ranged ability. The win condition for the PQ is downing her in 20 minutes.
Meanwhile, another group needs to be below to delay the losing condition of the PQ. Heroes will stream down from above to deactivate the stones that the players activated in stage 2. If engaged, they will overwhelm the players. So, players stand back from the stones, allow the mobs to deactivate the stones, then run in to turn them back on. Note that when the heroes interact with the stone, they cause AOE damage, so players should stand back until they need to reactivate. If the mobs deactivate all the stones, the group loses.
If Stage 3 fails, the players can respawn at the healer downstairs, with the quest reset back to the start of stage 2.