This quest begins with Ser Clifford Gower in the castle of The Weeping Town after you complete A New Beginning. He will give you a ring and a letter, which you will deliver all the way up to the castle of Ninestars in Vale (NEish in the Fingers). Make your way up there, and then ask to enter the castle and then go to the Tourney Grounds. Ride down, and on the left side of the campfire you should see an NPC named Alyn Tollett. Speak with him, then exit the area.
You will be faced with an option of whether to defend a peasant and his newly betrothed against a harassing knight and squire or not. Choosing to defend them will get you locked up, but with the option to ask for a trial by combat. Take the trial by combat and you will be facing off 1 vs 1 against Raymund Templeton, the harassing knight. If you are strong enough, you will be given some decent armor to wear if you have none.
Dispatch of him, and you will be on your merry way....but oh wait. Two of Raymund's family members get drunk and decide to chase you down on horseback. If you aren't particularly high level and your bodyguards are worthless/nonexistent, this can be tricky. I, personally, would try and unhorse one of them as quickly as possible. If the horse lives, ride that thang and slay. Otherwise, unhorse the other as well and fend the two off as best you can. Use the trees to your advantage to avoid their charges. There is also a small campfire in the woods to the right with a chest that contains a few odds and ends, nothing particularly exciting.
If you manage to defeat the two, you will walk away from Ninestars having completed the quest, gained a solid amount of experience, gold, honor, and renown. Strong work.