You're on the outside castle walls now. Go around to the idol doors with the circle above. She opens, go through, they slam shut. You're on a two part giant puzzle now, your aim is to get the main doors open. The part of the puzzle you're working on now will electrify the left hand door, and then later on you'll work on the right hand door.

OK, there's a big circle door with a sword stuck in it. Get her to climb the ladder to the save spot. Monsters will come, kill them. This is "East Arena". Both go through the door and climb on the circular thing. Stairs will appear to go up. Monsters will come. Fight them and go up the stairs to in between the torches. Pull the switch. Candles will appear on either side. Light your stick on a torch then light the candles. The door will open. Go through it to the grass. There's a save spot "East Reflector".

The Ico Walkthrough

Please swing by my Forum to ask me how to get through if you're stuck somewhere I haven't put up yet. I'll get back to you quickly.