Steal necklace from the Merchants

 is a side quest in the original Fallout.

Background
In The Hub's Old Town a building has a staircase leading down to the Thieves Circle. The player must navigate some traps and locked doors to enter the clandestine subterranean location. Inside he will find Loxley and his inner circle of thieves. Loxley will give you credit for navigating the aforementioned obstacles and offer you membership in the Thieves' Guild, provided you can steal a necklace from the house of an eminent local merchant. Loxley will grant 900 XP for simply completing the initial dialogue and accepting this quest.

Walkthrough
Daren Hightower's house can be found in the Heights district of the Hub. His house is heavily guarded, but if you sneak in at night, around 18:00 you should be able to make it in and out without being seen. Otherwise you might have to kill a bunch of guards. In a room toward the lower left of his house is a strongbox. There is a trap that will explode if you try to lockpick the box before disarming it, but inside is the fancy gold, silver and diamond necklace. Return it to Loxley in the Thieves Circle.

Rewards

 * 900 XP when you accept the quest
 * 500 XP upon completion
 * 3000 caps
 * Electronic lock pick