Within the Gerudo Desert, you infiltrate the Bulblin encampment and enter the Arbiter's Grounds.
Get a Key
Go straight ahead, then when you reach the sand, use the Clawshot on the target on the wall. Next, jump from stone platform to stone platform, but don't stay on them for too long, because they can sink into the sand. At the end, roll across the sand to reach the fenced-off area.
Kill the Stalfos that come up from the sand, then use the Clawshot on the metal handle to bring it close to you. Grab it and pull on it until the gate opens. Go through it.
In the next area, there is a container of lantern oil, so use it to refill your lantern if needed, and fill an empty bottle with oil as well, if you have one.
After getting some oil, go in the opposite direction and break through the wooden planks. Jump across the quicksand and open the chest to get a key. Go back to the locked door and open it.
Get a Poe Soul
The next room is dark, so take out your lantern. Large numbers of Stalfos will appear, so go around the room and kill them all, then light the two torches next to the locked door and go through it.
Try to go straight ahead in the next room. Some lanterns will float in and take the torch light. Transform into a wolf so you can see the poe. Wait for it to swing its lantern, then attack. After you kill it and take its soul, sniff it to learn its scent. Follow the scent to a patch of sand in this room. Dig up the sand, then pull on the metal handle that you find. Transform back into a human, then go down the new stairs and through the door at the bottom.
Get a Second Key
Kill the bubble that is floating around the room, then push on the thing in the middle to rotate it. A ReDead Knight appears. It can paralyze you with its scream if you get too close, but you can try to perform a Back Slice while paralyzed to avoid its sword. When it is dead, open the chest to get a small key. After that, use the Clawshot through the hole in the ceiling to grab the grating. Then find the door in this room and go through.
Get a Second Poe Soul
Go forward into the next room and kill the bubbles, then transform into a wolf, use your senses, then kill the poe and take its soul. Transform back into a human and leave this room the way you came in.
Get a Piece of Heart
Fall down the hole, then push the thing to rotate it again. Open the door and you will see a torch light up. Go up the stairs and look to the side, where there is some sand and a Clawshot target beyond it. Use the Clawshot to go across the sand, and open the chest there to get a piece of heart. Then use the Clawshot to go back across.
Get the Dungeon Map
In the northern part of the room, next to the stairs, roll across the quicksand to find a treasure chest that contains the Map.
Get the Compass
Go through the door that goes to a round room, according to the map. It's the door above the stairs leading down. The round room contains a column. Go straight ahead and unlock the door.
Go around the room to reach the cage in the middle. Drag it toward you until it falls, then push it into the gap. Then go up the stairs and pull the handle on the ground that is lying near the spikes. This will raise a round platform. Keep pulling until the round platform won't go any farther up. Go up the stairs that the platform was blocking. Kill the bubbles in the room, then go to the far end of the room and open the chest to get the Compass.
Get a Third Key
Now go to the statue in this room and rotate it, then go down one of the newly-revealed hallways to reach a door blocked with wooden planks. Break it open with your sword and kill the ReDead Knight. Then open the chest to get a key.
Get a Third Poe Soul
Go back the way you came and unlock the door past the rotating statue. Cross the quicksand and kill the Stalkin and ReDead Knights in the path. Then transform into a wolf and dig the small patch of sand to reveal a chain. Pull on it and use your senses to sense the poe in the secret room. Kill it and take its soul.
Get a Fourth Key
Now go the opposite direction from the secret room that the poe was hiding in, and go through the door at the end. Go down into the pit and look for a small chest on the side. Open it to get a small key.
Get a Fourth Poe Soul
Use your senses to detect the Ghoul Rats in this room. Hold the attack button to have Midna do a Dark Energy Attack on multiple rats at once. Afterward, go back to the upper part of the room, jump over the gap, transform back into a human, then go through the locked door.
After the cutscene, jump onto the chain platform and go across, and go through the door at the other side.
Go down the stairs and push the cage until it falls. Then go into the side room that was blocked by the cage, and open the chest to get a red rupee. Then climb up onto the cage and pull the nearby chain to lift the platform. Then walk under the platform and go to the end to find a chest. Open it to get another red rupee.
Go under the chain platform before it falls, and get in the middle so you are under the hole in the platform. When it lands, climb on it and jump down to the ledge with the door. Go through.
Break through the wood and walk around in the room until a cutscene occurs. Hit the Stalfos to make it fall, then kill it with a bomb. Before you leave the room, open the two chests in this room to get more bombs. Then leave the room through the south door.
Go up the stairs. Transform into a wolf and use your senses to see the poe scent. Look to see which torches are touched by the poe scent. Then transform back into a human and light those torches. Go through the door in the secret room.
Transform into a wolf and use your senses to see the final poe. It makes copies of itself. The poes will float around. Lock onto one of them. When they stop moving, the real one will glow, so quickly target and attack it before it can attack. When it dies, take its soul. Transform back into a human and leave the room through the north door.
Get a Fifth Key
Jump down onto the chain platform and use the Clawshot on the grate with the torch behind it. Go through the door nearby. The final poe soul will light the torch and the door will open. Go through it.
Next, go through the door that doesn't have torches beside it. Fall down to the bottom and rotate the room to make it go upward. There is a chest to the side, but spikes block it. You can get rid of the spikes with bomb arrows, or just go through the path that isn't blocked to go the long way around and open the chest to get a small key. You can raise the room more to find rupees in other side rooms. When you are ready to move on, lower the room and unlock the door at the bottom.
In this room, be careful of the spikes that pop up out of the ground. As a wolf, you can use your senses to see an afterimage of the spikes for a short time, to help you navigate more safely. You can destroy the spikes with bomb arrows. There are also ghoul rats that only Wolf Link can see using his senses.
At the far end of the room, go to the side to find a chain. You might want to use bomb arrows on the spikes that come up out of the ground nearby. Use the chain to pull the stone block out of the way, then go through where the stone had been blocking the path.
Roll across the quicksand in this area. Use your lantern to get the Poison Mites to leave you alone, or kill them with a Spin Attack. You can find Ooccoo in a pot at the end of this area. Go through the nearby door.
Reach the Mini-Boss
Go past the spinning spike thing and into the room on the far side. Kill the two Stalfos, then find the Stalfos in the side area and kill it as well. Go past the spinning spike thing and go along the quicksand path in a side room, carrying your lantern to keep the Poison Mites off of you. Jump over the gap and go up the stairs and go through the door at the end.
Cut one of the ropes to awaken Death Sword. Transform into a wolf and use your senses to see Death Sword. Sidestep its attacks so that the sword gets stuck in the floor. Attack Death Sword when this happens, and then transform into a human. When Death Sword is floating slowly, use the bow, clawshot, or boomerang on it. It will then spin rapidly around the room, then will slow down and come near. Dodge when it swings the sword. When its skull hangs down, hit it repeatedly with your sword. Repeat this until it dies.
Get the Spinner
Go through the small gate that opened, and go to the end of the room to find a chest. Open it to get the Spinner. Go to the side of the room and use the spinner to hit the track in the wall. When you are near the door, do a Jump to get off the track. Go through the door.
Get a Second Piece of Heart
Use the Spinner on the track on the side of the room, then when you are over the quicksand, jump to the track on the other side. Then deactivate the Spinner at the door and go through.
Use the Spinner on the tracks to go over the quicksand. Explore the lower area of the room to find bombs and rupees. Then use the Spinner on the track that goes up a ramp. It will drop you near a spinning spike thing, and you can find a small chest below the statue. Open it to get a Piece of Heart.
Get the Big Key
Then use the Spinner on the track, being careful to time it so you don't get hit by the spinning spike thing. Jump to the opposite side so you don't fall down when the track ends. Repeat this and the Spinner will land near a small stone circle in the quicksand. Get off the Spinner, then use it to get onto the track on the side. After you fall near the statue, get off the Spinner and look for a side room with a chest that contains a yellow rupee. Then use the Spinner on the track, and get off when the track has gone up a ramp and starts to curve. Go up the ramp that leads to a narrow path at the top, and use the Spinner on the track, jumping to avoid the Blade Traps. Go through the door at the top.
Open the chest to get the Big Key. Then use the Spinner on the nearby track to reach the other side. Use the spinner on the gear-shaped hole, and spin (tap the button rapidly) until the wall opens. Go through and use the Spinner to cross the quicksand and hit the track in the wall. When you are high up enough, jump to land on the circular platform in the middle. Use the Spinner on the hole on top of the platform. Spin until a spiral track comes up from below. Use the Spinner on it to go to the top of the room, then unlock the door at the top.
Twilit Fossil: Stallord
Walk toward the skeleton and there will be a cutscene. Afterward, use the Spinner on the track around the edge of the pit, jumping as necessary to avoid the Blade Traps that also spin on the track. Jump to hit Stallord's spine from the side or back (press the Attack button to attack with the Spinner when you are near the spine) while avoiding the Staltroops in the sand that block your path (you can press the Attack button to destroy these when you bounce off of them). After you hit the spine three times, the sand drains away. Use the Spinner on the hole in the middle of the floor to make a platform rise. Stallord will knock you off of the platform.
Use the Spinner on the track on the center platform. When Stallord's skull appears, jump to the outer wall to avoid the fireballs that Stallord tries to spit at you. Note that you need to be on the center platform to move farther upward; the tracks on the wall don't move you farther upward. When you get close enough to Stallord's skull after it spits fireballs, jump off of the track to hit Stallord's skull. Then repeatedly hit the sword that is sticking out of the skull. Repeat the process, avoiding the blade traps that appear, until Stallord is defeated.
Afterward, take the Heart Container and cross the bridge to go out through the door. Go up the nearby stairs, jumping over the gaps along the way, and go through an archway at the top. Make your way to the statue in the middle of the Mirror Chamber, and some Shadow Beasts appear. There are five beasts this time. You can transform into Wolf Link if you find it easier to fight them that way. As always, kill all but two of the beasts, then make sure to kill the last two simultaneously.
After they are gone, use the Spinner on the central statue to go up to the top, then use the Spinner in the hole at the top. A cutscene will occur.