Fast-Hands broke his leg in a climbing accident. The shaman Merrin has refused to help him, saying that he hasn't paid the proper respect to her (a snub on a previous matter that she's being petty about). You can take care of his leg, but it'll make her like you less.
Science Boy - Can use Medicine to set his leg. A decent skill can set his leg better than it is (leaving him with a limp when healed but otherwise OK), a good skill can set it perfectly (full recovery). He'll be grateful if you help him a little, but if you totally fix it, once it's healed (2 months) he'll go climbing again and present you some broc flowers and nara roots as a thank-you (he knows Merrin uses them for healing but doesn't know how, and assumes you do know how).
Fast-Hands, one of the Blackfoots, broke his leg in a fall. The Daughter of Hecate refuses to help him, apparently because he hasn't shown her the proper respect. Now his leg is poorly set and he's worried that when it's healed he'll be unable to walk or climb.
2
I broke and re-set Fast-Hands' broken leg so it would heal properly. He might have a limp, but he'll be able to walk and even climb when it's fully healed.
3
Quest finished
Now that his leg is fully healed, Fast-Hands brought be some medicinal plants as a thank-you for helping him.