Through the Quicksand Caves

Mission Information
Mission Name:	Through the Quicksand Caves
Expansion:	Rise of the Zilart
Starting NPC/Zone:	None
Description:	You must hurry to Zepwell's Island's ancient temple.
Level Restriction:	None	Repeatable?	No
Mission Series
Previous Mission:	Headstone Pilgrimage
Next Mission:	The Chamber of Oracles
Rewards
Title Granted:	None
Reward:	None

Walkthrough

Ensure everyone is on the mission "Through the Quicksand Caves". If not, they have not properly completed the previous mission, check key items to see which is missing.
You'll want a party of level 65+. You will be entering a BCNM fight against 3 Antica NMs, who all have a TP attack that will Silence (Jamming Wave), mages should all bring Echo Drops.
Head for a tunnel at (C-11) in Western Altepa Desert. Follow this outside to an unmarked area of the desert. Head down the ramp to (D-12) and enter Quicksand Caves.
Everything here aggros sound, so make sure everyone gets Sneak. You'll need to step on pads that require a certain weight. You'll either need 1 Galka, 3 Tarutaru or any combination of 2 of Hume/Elvaan/Mithra.
Go to (I-9) and step on the pad and go through the door.
Go west to (H-7) and use another pad to pass through a door. In the next room, drop down the hole to a hidden area. Head do (D-4) to zone in to the Chamber of Oracles.
Get ready and enter the BCNM. You'll be facing 3 Antica NMs

Defeat them in the order listed. Open with a Sleepga, and then Silence the Paladin and the Black Mage. Defeat the Paladin first, as he can rebuff the others, as well as wake them up. Keep the BLM silenced, to render its 2hr useless. Finally, defeat the RNG, but be careful of Eagle Eye Shot.
Upon clearing the BC, you'll zone in to another area of the Chamber of Oracles, which starts the next mission.

A dual boxed 75 BLM, 75 WHM and 75 THF/NIN can easily beat this BCNM. THF only took damage from occasional RNG attacks, and Magnetic cloud.