Trading 1 crystal to a Windurstian Conquest Overseer will unlock this mission after completing the previous mission.
This mission may be skipped by turning in a total of 3 crystals since gaining rank 3; however, if this mission is skipped, you will not obtain the Portal Charm. For this reason, if you are soloing missions, it is recommended that you not skip this mission.
Make your way to (E-10) and go through the Magical Gate of Horutoto there.
Continue straight west to a Cracked Door at (D-10) and go through to the next area.
Follow the path to the large room at (H-9). You'll find the Sealed Portal on the north side of the room. In front of this door are 3 circles on the floor - a whitish one, blackish one, and reddish one. This is the Three Mage Gate.
To open the gate have your Black Mage stand on the dark circle, White Mage on the light one, and Red Mage on the reddish one. They will begin to glow and the door will open. If you brought someone who has the Portal Charm, they just need to click on the door to open it.
Everyone needs to head through quickly - when the door closes, that's it. It cannot be re-opened from the inside.
Follow this passage a few steps to a round room with two hallways - one to the north-east, and one to the north-west. It doesn't matter which one you take - they'll both lead to the same place. They look like dead ends, but they're just false walls. Walk right through the wall at the end of the tunnel to find yourself in a room full of Wendigos and Battle Bats. This is Rose Tower, Map 2.
via Toraimarai Canal
There is a Survival Guide at (F-5) near the zone line to Horutoto Ruins. If you have previously activated it the trip to Rose Tower, Map 2 in Inner Horutoto Ruins takes mere seconds.
Follow the path and take the west path from the fork at (H-7). Head down the stairs into the water at (G-7) and continue west.
Turn north, then west at (G-6) to reach Map 1 of Toraimarai Canal.
Turn north at (J-7), then continue West until the path forks.
Turn south, go up the stairs at (H-7) to reach dry ground and then head north.
Cross the small footbridge to reach the eastern side of the dry ground, then follow the path until it leads you to Inner Horutoto Ruins at (F-6). The Survival Guide is nearby at (F-5) so be sure to activate it.
You should now be in Rose Tower, Map 2, behind the Three Mage Gate.
At the Gate of Light
Once inside Rose Tower, Map 2, head over to the small room in (G-7) (west side, north room) and click on the Gate of Light for a cutscene.
You can now safely warp home or return via one of a few options:
You can get back to the Three Mage Gate by walking into the glowing light on the platform in the east room at H-6. From here you can make your way back through the ruins the same way you came.
This mission has an alternate objective depending on your mission completion state. If you are repeating this mission or have completed The Final Seal after skipping this mission, Zubaba will instead ask for 3 Rusty Daggers as proof of her request to "clean up some vermin" beyond the Three Mage Gate.
On the command of Zubaba, the head lady-in-waiting, you are to journey beneath the central magic tower of the Horutoto Ruins. There, you are to report to the facility managed by Heavens Tower, which protects the talisman that seals Castle Zvahl. Render whatever assistance is necessary.
SPOILER WARNING: Click here for additional details about this story line.