You need to have Amren in your party in order to acquire this quest. He can be found near the bar in the Aman'lu Tavern, which is due west of the Aman'lu teleporter. Amren will mention visions when your group closes in on one of the mushroom circles. Once they actually get close to the first one they visit, a cut scene of Amren's Vision will be shown noting where all four mushroom circles can be found, plus showing the ornate chest opening at the end. Once they've found any one of the four mushroom circles, have them all stand within the circle and put Amren in the lead. Move the cursor around the circle of mushrooms until it lands on A Peculiar Mushroom and turns into a hand icon, then click on it to cause them to descend to a subterranean Mysterious Shrine hidden below. Notice that in each one of them, as they enter, they'll pass under an inactive portal. When the first circle is entered with Amren in your party...

Teleport from Eirulan to the Southern Greilyn Jungle. Razka's Ruins are just east of the Southern Greilyn Jungle teleporter. Skirt them to the northeast or southeast (actually sometimes just heading straight through can work just as well), then return onto the path heading east toward the Exile Colony, and following it up around the first curve. Then head west off the path when you spot a small clearing and you'll see the mushroom circle just a bit farther on. Put Amren in the lead and have them step into the circle amidst the mushrooms. The southern mushroom will glow red once Amren remarks about this being another (or the first) of the circles and can be used to activate the elevator by left clicking on it. Once below in the Mysterious Shrine, head east down the ramp, then turn south and move forward and grab Volume 17: The Path of Live from the shelf, then proceed to the end of the corridor and left click on the statue to have Amren disclaim about the Azunite Tree of Life, which completes this segment of the quest. Open the nearby Big Chest for some treasure. Exit the shrine unless it's the fourth one they've visited.

Teleport from Aman'lu to the Southern Vai'lutra Forest (North). Head north behind the teleporter a few steps, then turn west and the mushroom circle will be in sight. Walk along the ridge toward it and enter the mushroom circle. Put Amren in the lead and have them step into the circle amidst the mushrooms. The eastern mushroom will glow red once Amren remarks about this being another (or the first) of the circles and can be used to activate the elevator by left clicking on it. Once below in the Mysterious Shrine, head west and grab Volume 18: The Path of the Sighted Eye from the alcove to the southwest, then proceed to the end of the corridor, opening the Big Chest along the way for some treasure, then left click on the statue at the end of the corridor to have Amren disclaim about the Azunite Tree of Sight and he notes that they are all descended from the Azunite tribe even thought they are of different races, which completes this segment of the quest. Exit the shrine unless it's the fourth one they've visited

Teleport from Aman'lu to the South end of the Garden of the Ancients. Your party will probably be instantly set upon by multiple enemies (Snow Kurgans, Spewing Grangeflies, etc.), so be prepared to deal with them. Head north through the broken arches and follow the path up to and past the first two pine trees where the path curves to the east, and your party has cleared the low ridge to the northwest, then turn and proceed west a few steps until the mushroom circle comes into view and they can continue north toward the mushroom circle. Put Amren in the lead and have them step into the circle amidst the mushrooms. The eastern mushroom will glow red once Amren remarks about this being another (or the first) of the circles and can be used to activate the elevator by left clicking on it. Once below in the Mysterious Shrine, head west down the ramp, then turn south and move forward and grab Volume 19: The Path of Death from the shelf, then proceed to the end of the corridor, opening the Big Chest along the way for some treasure, then left click on the statue at the end of the corridor to have Amren disclaim about the Azunite Tree of Death, which completes this segment of the quest. Exit the shrine unless it's the fourth one they've visited.

You must have initiated Act III Chapter 2 (The Morden Chief) in order to gain access to this volume. Teleport from Kalrathia to the Ruins of Okaym, then first head north, then turn east toward the entrance to the Kalrathian Nexus. Follow the path past the entrance to a Large Abandoned Shelter, continuing to the south and then turning to the west. When you see a tower, and your party has not been there before, approach it, open the door, and enter to obtain some treasure and take the Greater Chant of Fighter Health from the lectern inside, then head back out and turn west. In either case take the path up the hill northwest past the campfire in a walled enclosure. The mushroom circle is in sight just around behind it. Put Amren in the lead and have them step into the circle amidst the mushrooms. The northern mushroom will glow red once Amren remarks about this being another (or the first) of the circles and can be used to activate the elevator by left clicking on it. Once below in the Mysterious Shrine, head west and get the Volume 20: The Path of Blindness from the shelf, then proceed to the end of the corridor, opening the Big Chest along the way for some treasure, then left click on the statue at the end of the corridor to have Amren tell about the Eye of Darkness, which completes this segment of the quest. Exit the shrine unless it's the fourth one they've visited.

After the fourth shrine beneath a mushroom circle has been visited (note that they can visit them in any order), a portal will open in the middle of that shrine. Turn around and head back toward the portal. Left click on the portal to teleport your party to A Mysterious Shrine. Have them head forward and Amren open the Big Chest for a unique bow (e.g. a Swift Bow, Snowy Swift Bow of Focus, Virtuous Rebellion, etc.) among other treasures.

  

Once they return to the portal in the Mysterious Shrine, they can use it to teleport back to any of the four shrines visited during this quest, which has now been completed.