The House of Curios is found in the Fields of Misery. An outdoor area in Act I of Diablo III, it is sometimes found in a small random map area called Lonely Dwelling (~5% spawn chance). Inside you'll find Adenah the Curio Vendor and Adenah's Jottings.
The player(s) may start on the quest from: Act 1, Chapter 5, Part 2. Teleport to the Cemetery of the Forsaken. Head northwest through the gate that may appear closed. It will save a checkpoint upon entering the Fields of Misery which you can leave and resume from. It also may be bugged where you have to start from here or you will never find it.
If one sees anything OTHER than the following, use a TP, leave game, resume, recycle:
- Waypoint (There is a WP in the screen shot so I don't think this is correct.)
- Khazra Den
- If you see Lost Mine or Scavenger's Den, you will not see Lonely Dwelling.
Following these steps, one should get the House of Curios quickly.