When you think of timeless Disney classics, you think of tales of princesses like Sleeping Beauty. However, you don't picture the tale taking place in a swamp-like hollow. Nor do you picture an undead Napoleonic army roleplaying rather badly as Prince Charming.
The Sleeping Beauty questline in Valor Mortis is yet another short and not so sweet tale, and one that you might need a little help getting to grips with.
So, here is how to find and complete this quest, as well as how to handle the decision at the end.
Finding Sleeping Beauty

To begin this quest, when exploring chapter six's Cursed Hollow, you'll want to go through a crack underneath a fence just before the corrupted area with all the spewer enemies. Through here, head to a tree surrounded by some poison water where you'll find a Shrike Shrine and a letter from a girl who fears her father has gone mad. This sets you on a quest to find this crazed madman and save this poor girl.
Follow the wooden beams, and you'll enter a house where you'll find the very man you're looking for. A mini-boss version of a Shambling civilian. It's a pretty basic fight, with the only gimmick you need to know being that he mostly uses unblockable attacks, so dodge, don't parry.

Defeat them, and you'll get the Headsman's Key, which will open the door to the building that you passed just after crouching through the crack in the fence. Loop back around, and you can enter to find the girl.
Should You Wake The Girl Or Let Her Sleep?

Unfortunately for the girl, she was all too right about her father, as he thought in his infinite wisdom that treating TB with the plague was a solid solution. But all it did was leave the girl in a coma-like state, eternally suffering.
So, you have a choice to make. You can either take out the spindle wheel, which will wake the girl, and you will be forced to fight her and put her out of her misery. Or you can increase spindle production, engulf her in the plague, and let her drift off peacefully.
There is a good choice and a bad choice as far as rewards are concerned, and this is what you'll get for each outcome:
- Wake The Girl: Pure Transmutation Material + 2,000 Catalysts
- Let Her Sleep: Superior Transmutation Material + 3,000 Catalysts
In short, it's the more humane and more lucrative option to let her succumb to the plague and die peacefully. Although, if you ask me, neither is all that much of a happy ending.