With the clawshot, there's a lot of places we couldn't reach before that we can now. There are three supply caches around the room for you to get up to (look for the target icon thing) with rupees and hearts. When you are done, use the clawshot on the target near the southern door to pull down the mechanism and open the gate. Go through. You can use the clawshot on those little masked things to de-mask them and then slash at them. Go south and then east to head back to the central room. The water level will rise. Go up the stairs and right to head back to that room we turned on the water in. Go up the waterslide using the iron boots and the clawshot (use the clawshot on the targets around the walls). When you reach the top, use the clawshot to get behind the waterfall. Open the chest for 20 rupees. Go back to the center room and use the clawshot on the target in front of you. Follow the waterslide down and go through the door. At some point here, you can use the clawshot when on the level right above the boss door (in the center room) on some seaweed growing on the wall, which gives you access to a chest containing the map. Go forward through the waterwheel and then, when you get into the open room, jump onto the first hanging platform. Look up and to the left and use the clawshot on the target on the gear. Lower yourself down to a chest with 10 bombs.

Look north and up from there and clawshot the seaweed on the wall of one of the pillars. Climb over to the little ledge. Look up and southeast from there and clawshot to that seaweed, too (hit it in the middle or you might fall off). Climb to the ledge. Look east (not up) and clawshot that seaweed. Climb over and go through the door. Look right and up and shoot down the stalagmite. Climb on it when the water is low, and then jump over the wall when the water is high. Go forward. Use the clawshot to get over the raised part and go through the door. There are two of those bubble monsters in here. Use the clawshot to pull them out of their bubbles and slash at them. Look up and to the left and clawshot the seaweed on the ceiling. Go forward and drop into the water. Climb the slide. When you reach a gap, use the clawshot to get to the other side when the water isn't bubbling up. Continue forward and there's another clawshot point. At the top there's a chest with 10 bombs, a pull lever to turn on the water, and a compass (behind the waterfall). Jump down into the water (watch out for the skullfish, which you can catch with a fishing rod but won't be added to your journal) and pull the chain on the center island. Exit through the algae and go out the left (southern) door. There's a 20-rupee chest in this pool (you can use the clawshot to kill those jellyfish now). Go into the gear room. There's a 20-rupee chest in the northwest corner; use the clawshot target near it to get it. Clawshot to the seaweed-covered pillar you climbed up using to get back to the rest of the area.

Exit to the northeast, like when you first came in. Turn left from that door. Go through the waterwheel to get a chest with 15 waterbombs. Go back up into the slide room and turn right through the door to get on the other side of the hallway. Get back on the gears and head southwest. Turn left for 20 more rupees in a chest. Turn around and use the clawshot point on the ceiling to open the door. Go through and head back to the center room. The water level rises again. Use the clawshot on the targets near the chandelier and drop onto it to get a piece of heart. Drop into the center water and go down to one level below the heavily locked door (swim to it and use the iron boots) for 20 more rupees. Climb up and exit using the east lower door. Use the clawshot on the gear bottom and spin until you are at the eastern-most island that you can reach. From there, clawshot up onto the eastern gear and drop onto the eastern island with the door. In the next room, swim left, down, go through a door, take a hard right, go up, and use a bomb on the rock. Go to the right and down and use a bomb on the rock. Swim up and go through the door. Kill the bubble-monster. Look up and use the clawshot. Lower yourself down to the big key chest. Jump into the water and open the door (while wearing the iron boots). Go through the tunnel and swim straight up. On the surface of this area is a chest with water bombs. Head back to the center room. Before we head to the boss, we're taking one last trip to the western room. Go to the lower western door. Pull the stairway chain so that the water is flowing into the western room. Go into the western room. The water will rise. Go across the now-raised bridge and stand on the raised tile in front of the gate.

While standing on the tile, clawshot into the room near the chest and kill the lizardman. Open the chest for a piece of heart. Use the clawshot on the point on the ceiling outside of the gate to escape. Go back up to the entrance and jump onto one of the hanging platforms. Take it to the western door. Go down the ramp into the water with the iron boots. There are two holes in the wall with bubbles coming out of one and going into the other. With the iron boots equipped, walk into them and (on the one that is the source of the bubbles) turn when a room opens up. Get the treasures: 5 water bombs and 20 rupees. Now head back to the center room. Find a way into the water in the center (you may have to use the iron boots to walk up the stairway).However you do it, go onto the little onion-shaped isle and unlock the door. Fall into the hole. Drop downwards with the iron boots. An eyeball spots you, and a bunch of tentacles come up. Now you fight Morpheel. Keep a distance from him and target his eye with the clawshot. Yank it out with z-targeting and slash it with your sword. If you get grabbed, you'll get chewed up and spit upwards; swim away to a safe distance.

After you hit his eye, bombfish will come out of the creature's mouth. Do it again and his full eel form will come out. You have to swim up and clawshot its eye (you can use the clawshot while swimming). When you grab on, attack it (like a normal attack, not with the A button). The whole thing plays out fairly "Shadow of the Colossus" style. Keep doing this until it dies (it was three times total in this part for me). Try to cut it off, because it swims faster than you, so swim to where it looks like it's swimming. Get the Heart Piece and the last fused shadow. Teleport outside.

Zelda Twilight Princess Walkthrough