After making it into the City Gardens and deactivated the Sand Gate, you will encounter a large round sunken arena which is patrolled by four Sand Guards. After you have speed killed them both with "double kills" and have dropped down into the arena, you will be confronted by the Stone Guardian, which is actually just a Thrall from Prince Of Persia: Warrior Within with a different look, which means you will initially deal with him in the same way. Once you are in front of him, roll between his legs then attack the back of his ankles. Eventually he will drop to one knee, just like the Thrall. Climb up on his back, just like the Thrall, but this is where the similarities stop. After climbing up on his head you will stab your dagger into the back of his neck, which will enable you to steer him like the chariot. Once you gain control of him, lead him through the large, closed, wooden door in the arena then through another door in the adjoining room. As he is running, the giant speeds up and this makes it much more difficult to control him. However, if you brush him up against the walls, he slows down to a manageable speed. However, make sure you only brush the walls or he will crash and land on top of you.