The Lost City - The Timekeeper's Crypt

The entrance to the crypt is located in the flooded area in the southwest corner of the city, where you fought the 3 Deathless warriors. Jump into the water...

...and swim into the submerged building on the north side of the pool. Inside this building, swim to the left (west)...

...and follow the flooded tunnel until you can surface and climb out of the water.

Continue through the tunnel until it widens into a room with carved niches. Here you'll find a mural (1/3) on the right, and a crumbling wall on the left. The mural is Valentinus, The Timekeeper from the Crypt Murals series. Examine it for XP and Greek. Then break through the wall and continue.

A little farther along, the passage turns and there are niches carved into the wall and a document (3/8) sitting on the floor. This is Valentinus, The Timekeeper from the Crypts of the Founders series (also XP and Greek).

Continue along the tunnel, collecting mushrooms and ore along the way. At the end of the tunnel is a ledge overlooking a pool. Ignore the pickups on the other side of the water for now. Drop into the water and swim to the left (west)...

...through the archway and into the crypt.

Pick up a stack of gold coins behind the sarcophagus. Then open it to unlock the ANCIENT QUIVER, which is automatically equipped. This lets you carry 10 more regular (silent) arrows plus 3 extra fire arrows, 2 extra poison arrows, and 2 extra explosive arrows. You also receive an XP award and 3,000 Expedition Credits for completing the crypt.

Swim back out into the cave and climb out of the water on the stone ledge on the right.

Jump across the water and grapple the ledge above.

Climb up to find mushrooms and magnesite. If your inventory is full, craft a few poison and explosive arrows to make room so you can then gather these resources. You should be able to do this with the increased carrying capacity the new quiver provides.

Swim across to the east side of the pool and climb the rock wall. Return through the tunnel the way you came.

When you reach the flooded passageway, swim forward through the two stone arches. Then turn right to get back to the wooden floor with the holes, where you can surface.