Ascalonian Catacombs Guide lies in the Plains of Ashford (Phasmatis Corridor).
At first, you should make a group, in which you'd better invite a guardian to assist you finish the story mode better.
After you entering into the grave, find the Rytlock and talk with him, thus the story begins. Rytlcok will ask you to look for a thing called Eir Stegalkin. There are some points needed to be note on the road, see the picture below:
There are enemies hidden in the coffins I marked, so what you need to do is open them one by one and kill them in case of danger. Only find golden monster hidden in one of the coffins can you open the first door.
After opening the door, walk along to the left side in that there are lots of dangerous traps in the right. You need to find out the way to ban the traps and open the second door. Kill the Captain Ascalonian at the end of the tunnel, where you can find out the Eir Stegalkin. Please note that there are 16 monsters including the captain in the room, therefore, you should coordinate with your teammates to wipe out all the enemies smoothly. While you kill the Captain Ascalonian there will appear a tiny chest, then the map will show as below:
Kill the Mage Nente, Ralena and Kasha one by one. Among them the Nente is a ranged mage, so watch out his range AOE attack. While the Ralena is a melee mage, we do not resist it as much as possible and it can be killed with kites. The last mage Kasha will call up skeleton, which is pretty dangerous. We'd better kill him before he summons amounts of skeletons.
The final step is to kill the King Adelbern. Pay attention to the king will pull you to him and give you a fatal strike, however, do not worry, the strike means nothing to you as long as use your endurance appropriately to roll. The task comes to the end when killed the king and corresponding reward will be presented to you.