During your explorations of the slums part of the Temple Quarter, you'll encounter a thug who will tell you about a haunted house with a treasure inside. However, when you enter the haunted house, you'll discover that the story was a trap, and four bandits will attack you.

After defeating the bandits, you'll find a half-elf girl imprisoned in the house, and when you rescue her (by talking to her) she'll tell you to meet her in a house in the non-human sector of the Temple Quarter. When you find her there, she'll quiz you on the elven language, and as long as you don't select the "stupid white wolf" dialogue option, she'll end up having sex with you.

Note: The Temple Quarter overview page shows the locations of the various houses involved in this rendezvous.