The Prison Gate is a landmark in Xenoblade Chronicles. It is located on the ground floor of Prison Island. This location differs at the middle of the story progression, during the midgame visits, and at the end of the game with several changes involving new transporters, enemies as well as Collectables.
Prison Gate (Midgame)
The Prison Gate is visited when the party accesses to Prison Island for the first time. Upon arriving at this location, the gate is locked. Melia uses her Staff to unlock the gate, so the party can proceed inside and enter the Central Hall.
Prison Gate (Endgame)
The Prison Gate changes when the party visits Prison Island at the end of the game. Since the gate is unlocked, it will automatically open up, just as it did during the time before the Bionis' Awakening. And just like before, it leads to the Central Hall. At first, along with every bit of the path to the Prison Gate, there is no music. But as soon as the party gets near the opened gate, The End Lies Ahead will play.