Talk to Leah. Doing this will result in her joining you in the next adventure.
Go to the Drowned Temple
Use a waypoint to travel to the Fields of Misery. Once you're there locate a passageway leading to The Old Mill.
It's best to find the main path and to remain on it during the journey. Keep moving forward until you encounter a Scoundrel who will ask you for help.
Follow the Scoundrel
Follow the Scoundrel to the mill.
Talk to the Brigand
Talk to one of the Brigands. Sadly the negotiations about letting the innocent woman go will end in a failure.
Kill the Brigands
Kill all the Brigands that are guarding the woman. Another group will soon exit a nearby a house and one more group will arrive from your left. You must kill all enemy units.
Speak with the Scoundrel
Approach the Scoundrel to have a word with him. He will join your team.
Take the Scoundrel north to the waypoint
Choose the northern gate to return to the Fields of Misery. Follow a narrow path until you've reached a new waypoint. Scoundrel will offer his services to you here, however if you agree to that you will have to say goodbye to the Templar. It's worth knowing that if you let the Templar go he will return to the town square in New Tristram and therefore you will be allowed to change your mind again if you won't find the new party member helpful.
Go to the Drowned Temple
Descend the stairs to reach the temple.
Talk to Alaric
Use the next set of stairs and then talk to Alaric.
Go to the Festering Woods
Follow Alaric by going to your right and wait until he has repaired a bridge, allowing you to move on with your journey. Cross the bridge to enter the dark forest.
Retrieve the Beacon of Honor from Warrior's Rest
Retrieve the Beacon of Light from the Crypt of the Ancients
The Festering Woods are a rather large location and aside from the well-known monsters you'll also encounter several new types of creatures here. Thankfully most of them won't be a serious threat. You should only watch for Enraged Phantoms, because they like to appear and disappear without warning and they can slow you down. It's worth adding that there's a new waypoint in the forest.
Your primary objective is to locate entrances to two underground locations - to Warrior's Rest and to Crypt of the Ancients. Each dungeon contains one of the artifacts you seek.
Crypt of the Ancients is being occupied by Returned Summoners and by the standard versions of the Returned that are being summoned to the battlefield. As usual you should always begin by killing all the summoners you've encountered. Be careful while exploring the crypt, because it's big and you'll be dealing with large groups of monsters.
Make sure you've killed all monsters and take the Beacon of Light from the pedestal. The area where the beacon is being stored is small, so you can't miss it.
Warrior's Rest is a fairly small location and you'll be dealing mostly with skeletons and archers while exploring it.
Continue exploring the crypt until you've located the Beacon of Honor.
Beacons placed on pedestals
Return to the Festering Woods, locate a waypoint mentioned earlier in the text and once you've found it use it to travel to the Drowned Temple. Alternatively you can cast a town portal spell to return to New Tristram and then interact with the waypoint located in the town's square. Either way you must return to the area where you've first met Alaric. There are two pedestals to the left and to the right of Alaric and you must place the beacons on them.
Enter the Drowned Temple
Head down to meet with Alaric. An entrance to the temple will open.
Explore the Drowned Temple
You may begin exploring the Drowned Temple. Cross a narrow bridge, eliminating Returned Summoners and the Returned along the way. You'll soon encounter Ezek the Prophet and thankfully he's very easy to kill, because his attacks are slow and he's not that tough. Besides you can count on Leah and on your mercenary to help you.
Soon before his death Ezek the Prophet will summon three of his brothers to help him - Brother Moek, Brother Larel and Brother Karel. They're weaker than him, however there's three of them and their attacks are much faster. Aside from the main boss and the three brothers you'll also have to watch out for several Returned Archers, especially since you can't hide from them anywhere.
Talk to Alaric in the Drowned Temple
Once you've killed all enemies locate Alaric standing where you've first encountered Ezek and talk to him.
Secure the Glowing Sword Shard
Notice that a nearby passageway was opened. Head over there and expect to have a second encounter with Maghda. This time she will summon several Dark Zealots.
Get the Glowing Sword Shard
Deal with the zealots and once it's safe collect the second part of the sword.
Return the Glowing Sword Shard to New Tristram
Travel back to New Tristram to end this quest.