|Spoiler Alert! This article describes a subject that is sensitive to plot development.|
When Link heads to Hyrule Castle in the past, wielding all three Spiritual Stones, he will witness Princess Zelda riding out with Impa, and Zelda will throw the Ocarina of Time into the moat. They are closely followed by Ganondorf, who questions Link a bit. So Link heads to the Temple of Time, in which he plays the Song of Time, and picks up the Master Sword, which is his ticket to the Sacred Realm. Trouble unfolds when Ganondorf follows him in, when he wields the Triforce of Power. 7 years later, Link awakens as the true Hero of Time. He goes to the Market to find out it is in shambles, and inhabited now by ReDeads. If he goes up the path to Hyrule Castle, he will realize Ganondorf has destroyed it, and built a new Castle in its place, Ganon's Castle.
Entering Ganon's Castle
Once Link has completed the 5 temples and awakened the Seven Sages, he can head to Hyrule Castle, where the Sages, now congregated, will create a magical bridge across the sea of lava. Link can now simply go across it and enter the large doorway to appear inside Ganon's Castle.
Ganon's Castle has rooms corresponding to the 6 Temples; the Forest Temple, the Fire Temple, the Water Temple, the Shadow Temple, the Spirit Temple, and the Temple of Light. Each one has a barrier that Link must destroy with Light Arrows, which will allow the Sage of the corresponding Temple to destroy it. Inside the Shadow Barrier section, Link will find the Golden Gauntlets, which are needed to finish the Fire Barrier. (Also requiring the Gauntlets, there is a secret outside, behind a giant grey rock, in which the Great Fairy of Courage is hiding. If you play Zelda's Lullaby, she will enhance your defense, meaning you take half damage from enemies.) Back inside, with all barriers destroyed, Link finally enters the door, and climbs the long staircase to face off with The Great King of Evil, Ganondorf.