Location: Baidi Lake
Prerequisite: Complete Dance at Qingmu Sect
Petitioner: Shangguan Hong
Reward: Icebolt Swordplay manual, Guaynin Advanced Blueprint, Martial Arts Perceptions, random items

In order to trigger this side quest you need to both complete Shangguan Hong's previous quest, Dance at Qingmu Sect, and raise her Affinity with Yi to at least 70. Hong likes swords, accessories, and anything related to tea, so it's not too difficult to get into her good graces. Once you reach an Affinity of 70 Hong will automatically bring up this side quest.

Assuming you jump to this quest immediately after Dance at Qingmu Sect, you'll find your next destination, Baidi Lake, just north of Qingmu Sect. To reach it you'll need to take a right from Qingmu Sect and go around the water separating the two locations. There's a little mountainside path that will take you down to Baidi Lake. (And if you don't remember where Qingmu Sect is, check the southeast of the map. It's near Gusu City.)

Baidi Lake is a nice, quiet place, and you can freely mine here if you ever need Jade Ore. Head east through Baidi Lake, over a bridge, and you'll find the members of Qingmu Sect waiting by a small shrine. A cut scene follows, and you'll discover that the final trial of Hong's journey is to defeat the leader of Qingmu Sect.

Mu Haitang

The final showdown. Hong will need to face Mu Haitang alone, so suffice it to say that this isn't an easy battle unless you try it out late in the game, when Hong is overwhelmingly powerful. Mu Haitang uses the following attacks:
  • Normal and enhanced sword thrusts
  • A variety of multi-directional line attacks
  • Taihua Twelve Swordplays, a strong, multi-directional line attack
Haitang is, in short, a pretty standard swordswoman - she's just strong. If you find that your Hong is lower in power than Haitang you should use Lightness right off the bat, then consistently get in behind Hong and strike her from behind. Haitang can only hit in straight lines, so if you need to back off and heal you can stop at angles to her and wind up perfectly safe.

Defeating Mu Haitang will earn you the rewards listed above. You'll also receive the Yuchang Sword, a powerful piece of equipment for Hong. Check the chest next to the shrine for Jinchuang Ointment, Mineral Drugs Powder, and Two-Time Refined Spirit Pills. This ends the quest - though you're not done with Qingmu Sect yet. If you revisit Qingmu Sect you'll find that Sima Ling, Hong's friendly rival, has a side quest for you - and it will take you down the path to recruiting her to the party.