Zelda Twilight Princess Walkthrough - Part 9 - Slip Slidin' Away
Warp to Zora's Domain, and goto the red target (a cave right next to the water, with a Zora standing near it). Go into the cave and arrive at Snowpeak. Talk to Ashei and find out that there is a beast looking for his favorite fish. She gives you a sketch and tells you to research it. The person that knows about it is the Zora Prince.
Warp back to Kakariko and goto the graveyard, and then through the crawlspace to where you got the Zora Armor. Talk to Prince Ralis and show him the sketch you just got from Ashei. He explains about Reekfish and how you need to catch one. It's near the "mother and child" rocks and you can only catch it with his Coral Earring. Also, he's going back to Zora's Domain! Not that you care.
Warp back to Zora's Domain and goto the base of the waterfall. There should be two rocks in the water (like a mother and child) and you need to fish near there. Use your fishing rod and throw it into the water near the rocks. Pull back as soon as it goes down, and you should catch a Reekfish. Turn into a wolf and smell the reekfish to learn it's scent.
Now that you know the reekfish scent, you can sniff out where the monster is. Follow the scent into that cave and into Snowpeak. Follow the scent up the mountain and kill any enemies you come across. There is quite a blizzard up here, so be careful. If the scent goes up a cliff-face, look for an alternative path to the left or right. Once it looks like a dead-end, headbutt the icy cliff to knock down some snow. There is a Wolf Stone up here near the edge of a cliff, so watch for it.
When the path comes to a dead-end finally, dig where it ends to arrive in a cave. Climb up the ladder and keep going, killing the bats along the way. Open the door at the end and you're on the peak of the mountain! Some twilight monsters show up, so kill them to open a warp point (you can warp to Kakariko to learn to move you just unlocked with the wolf stone).
Walk up to that big white monster near the tree and talk to him. He will talk to you and eventually tell you to follow him down the mountain. So roll into the tree to make an ice-sled fall down, and then get on and bust a move. Nothing special here, just don't fall into a cavernous abyss. At the bottom of the mountain, go inside his big mansion.