quote Insanity Prevails

Close. When you've reached the summit of the mountain where the owl is waiting there are actually two entrances. The right one is to the crater, but that's not what you want.

The left-hand entrance is sealed up, but a quick bomb will deal with that. Go through that to reach the Great Fairy Fountain.

i disagree on the part that you dont want to enter in the crater, 1st make nigth enter destroy the box, collect the skulltula, get out, enter go and blow the rock in the center get out, enter fall in the hole, now if the timer is abou 3 to 4 min you have in off time, climb down the wall get the heart piece, climb the same wall up enter in the hole, now exit go behind the owl blow up the wall, enter use your ocarina and use zelda lubally, obtain the power of Din, if its still nigth, grab the owl, and he will drop you on a roof of Kakariko, kill the skultula, and carefully drop down on to the left side of the house, you should be on mini roof go to the door and reclaim a new heart piece.