Start by fighting all of the enemies, then jumping up the ledge to the left of the path. There should be two chests here - one with experience and another with magic. Use Poseidon's Rage to defeat the enemies in the area and then open up the magic chest to get your magic back. Now jump up the ledge in front of you and you'll come across a fight with four Minotaurs. Use Medusa's Gaze to defeat them quicker (or otherwise go with the longer alternative) and then kill the Undead Archers. Eventually, you'll reach another ledge where you'll have to fight two Cyclopes and two Minotaurs. Again, use Medusa's Gaze if you're having trouble. Then kill the Archers and jump up the next ledge. The spiraling staircase will take you back to Athens with the pull of a lever.
Go forward and you'll reach the area where you first saw Ares. Instead of going down the left path, go down the right path this time around. If you've been there before, you'll notice that the door that was once closed is now open. Open the chest by the door for a Gorgon Eye, then go through the door to begin your journey to Pandora's Temple through the Desert of Lost Souls.