Okay, you need to be fast. Jump on the horse and immediately follow the signs to the cemetery. Talk to the boy in the corner and bury his father, and get the key from him for the church. Go inside the church and run out the back door. Run up to the third grave on the right, and hit . Run over to the stone shown in the cutscene and hit . Run forward a bit and look at the boulder on the cliff above you. Run back to the church, climb the rocks on the left side, and follow the long path to the boulder. Swing from the branch and kick the boulder down the cliff, then run inside the hole it reveals.