There's a woman called Kaitlyn waiting near the front of the village chantry and she’s crying. It seems that her little brother Bevin has run off and she can’t find him. She doesn’t really know where to look, but that’s okay. I already do. Promising to find the boy will net you a +1 approval from Leliana.

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The boy is just inside Kaitlyn’s House. It’s marked on the map and it’s very close to the chantry. Go inside and walk into the little bedroom on the first floor. You’ll hear someone moving around in the dresser. Talk to the boy and get him to come out. You can ask him what’s he’s doing and either persuade or intimidate him into revealing the truth. Apparently his grandfather’s sword is inside the house somewhere and he wanted to use it against the monsters. He can give you the key if you pass a persuasion or intimidation check, but you can also just promise to tell his sister and pay for it. You don’t actually have to do this though, so it’s a suitable option if you fail the speech options.
Go upstairs and use the key to open the chest and get the blade. The official end of the quest is a little complicated though. The easiest way is to go back and tell her to stay safe. Leliana’s approval will go up by 1 and that’s it for the quest.
You can wander into the minefield of buying the sword or having some fun with roleplaying. You can pay up to 500 silver for the sword if you’re feeling generous. Alistair and Leliana naturally appreciate your actions, since you’re being fair and giving them the money to evacuate to safety and stay out of an orphanage. Sten will also get offended if you pay less than 100 silver, since he believes that the blade is worth more. Morrigan thinks your just wasting your money at the good prices though.
You can also wait until after the battle to pay them for the sword or just give them some money for roughly the same effects.
Finally, you can ask for a kiss as your reward. If you follow through with it, you’ll gross out her brother and lose 10 approval points with Leliana. Stopping partway and saying you just need her smile will cause Morrigan to lose a few points.
So, I suggest you just keep it simple and tell them to stay safe for now.