Once you have collected all three stones, head towards Hyrule Castle. As you approach the drawbridge, a movie sequence will begin. You may recognize this motion picture from the very beginning of the game in your character's bad dreams. Zelda and Impa will gallop past you on a horse, and Zelda will throw something into the castle moat. Before you can retrieve it, however, Ganondorf will come out of the castle. When you try to put up a fight against Ganondorf, he will laugh and smite you to the ground with some type of magic. After Ganondorf rides away, jump into the moat and have a look around. You will see something on the bottom. Dive and pick it up.
It will be the Ocarina of Time and it will replace your Fairy Ocarina on your Item List. Once you pick it up, another movie sequence will begin, starring Zelda. She will teach you the Song of Time and tell you to hurry to the Temple of Time. Enter the Temple of Time and play the Song of Time on the crest on the floor in front of the hip-high shelf. The stones will be set in that shelf and the blue door will open.
Walk in and pull out the Master Sword. When you do this, Ganondorf will appear. It turns out that he followed you to the Temple of Time, knowing that you were the key to it. You will be sucked into a void for seven years. During that time period, Ganondorf will have stormed the Golden Land and taken the Triforce. You will awaken in the Room of the Sages. You will meet an old sage, named Rauros. He will explain your next quest, which is to go to each Sage's Temple and to help out the sages. He will also give you the Light Medallion.
Part of your new quest is to recover the other five medallions. The world has changed greatly in seven years. You are now told to visit Kakariko Village. Talon from Lon Lon Ranch is staying here as well. Awaken him with the miniature chicken that a girl gives you (please refer to the "Item Trading" summary for more information on this. This is not the true purpose of going to Kakariko Village, though. You may learn that Dampe the gravedigger is dead. Enter the Kakariko Village Graveyard and you will notice a new tomb near the wall on the left. Pull the tomb from behind and jump down the uncovered hole. You will meet Dampe's ghost down there, and he will challenge you to a race. If you keep up with Dampe well enough, he will reward you with the hookshot.
After this, many people are stumped, because it appears that a blue stone is blocking your exit. Play the Song of Time and the stone will disappear. Play the Song of Time every time you see a similar-looking blue stone in the future. This exit pathway will lead you into the windmill, where you can finally get that piece of heart. Also, you can learn the Song of Storms from the man in the windmill. I would now head to Lon Lon Ranch. Talk to the new manager Ingo until he asks you if you want to ride a horse. Pay him the money and do this. Before you hop on a horse, though, play Epona's Song. A horse will whinny and run over to you. Yes - this is the pony Epona that has now reached its full stature. Ride the horse until your time is up, and then play the Sun Song.
Now that it is night, go into the middle of the large corral and talk with Malon. Play Epona's Song for her and she will remember you. Now play the Sun Song again and talk to Ingo. Pay him to ride the horse, play Epona's Song and jump on Epona. While on Epona's back, talk to Ingo. He will challenge you to a race. I cannot offer much help with the race - just try to stay to the inside of the track and do not run out of carrots, for they are bursts of speed that you will need throughout the race. If you win the first race, Ingo will challenge you to a second race. If you win this, you will get to keep Epona. If you win, however, Ingo will play one last trick on you. He will lock you in Lon Lon Ranch. To escape, spur Epona towards one of the stone walls at the other side of the corral. If you are going fast enough, Epona will hop the wall and emerge outside of Lon Lon Ranch. From now on, you can call Epona to you from just about anywhere by playing Epona's Song.
Riding the horse will greatly increase the speed with which you go around the world. Your next stop should be the Forest Temple, which is covered in the next section...
Proceed to Forest Temple...