It’s an optional quest, linked to Ray, i.e. the man who stole from the protagonist. After finding Ray you will be able to cooperate with him, which may lead to Ray permanently joining the team. In this quest, you can help Ray to get to The Fort and finding Wyatt there.
How to unlock the quest: Talk to Ray in Sandy Pines.
The easiest way is to unlock this quest during the Stolen Equipment main quest, since the thief that stole from you is involved in this quest. You can find Ray in the Sandy Pines motel, located to the north of Goliet. After finding him, you have to click through all possible dialogues to start working with him (the For a Handful of Shards will automatically get cancelled, since it requires hunting for Ray).
The Fort is the Outlaws’ headquarter and you can find it southeast from the motel. Ray can be found near the entrance to the city. Entering the fort will be interrupted by a guard called Spike, who will demand payment. You can give him 200 Elexit, attack him (fist fight) or use the Suggestion. If you don’t feel like wasting your precious time for this dude, you can fly over the wall with your jetpack.
Reach Wyatt with Ray (200XP) and talk about one of the bounties submitted for Ray’s head. You get 400XP and a Contract for Ray. There’s nine more of these, but that’s a part of the For a Handful of Shards quest. You don’t have to devote to that quest right away, because right now, Ray will become your permanent companion, traveling with you (500XP).