Obi-Wan and Anakin battle on the top of the multispired collection panels, jumping from one to the other and with each jump, their sabers collide. At the end of the collection cluster, a huge spray of lava covers the attachments that hold up the collectors above. The frame begins to melt as the lava rains down. They both run for cover under the collection vats hanging above (both going to different vats apart from one another). They briefly run out form under the collectors and briefly strike their sabers together until another wave of lava comes down and they are forced to dart in opposite directions to avoid it.
Support for the entire structure begins to fall away, and the collection cluster falls into the lava river. They both leap away at the last minute, grasping a tall tower nearby. The Jedi continue their fight as they hang on the side: Anakin bringing his saber down, only for Obi-Wan to deflect. As the lava begins to eat away, Obi-Wan quickly leaps over Anakin's head and begins climbing to a higher point. The tower rides the swift current down the river as Anakin climbs after him, swatting at his feet as he gives chase. It bends toward the lava as they get out toward the end with Obi-Wan getting to the end. The tower slowly starts to sink under the lava and he soon realizes he is trapped.
Outside the Senate building, Bail is in his open cockpit speeder and flies along next to the roof. He slows and moves closer to a long row of recessed lights. Suddenly, Yoda falls out of one of the light recesses and lands next to him. Bail guns it and heads away from the building as the Jedi straightens himself out. "Into exile I must go," he states sadly, "Failed, I have." They fly into the traffic of the city and disappear.
Meanwhile, Obi-Wan realizes he is getting very close to the edge of the lava falls as the tower sinks. He grabs a rope and leaps from the collection arm, swinging away from his opponent who makes one last desperate swing. Anakin leaps and grabs another cable, swinging toward a rock wall before kicking off and making his way back to Obi-Wan. They swing past each other and their swords collide. They both hang in the air momentarily before going back for another pass where they once again strike blades.
Then they both spot something that causes them to stop fighting: the lava river ahead drops off in a tremendous lava fall. Snapping and metal groans are heard as the main part of the collector starts to break away and move toward the lava fall. Obi-Wan looks around and sees a small floating platform making its way toward the tower. He does a double back-flip and lands squarely on the floating platform. He then immediately leans to one side and moves away from the tower.
Anakin realizes he is doomed as the entire tower heads for the falls. In the distance he sees some construction droids. He swings back to the tower, climbs up and makes a running leap, then miraculously lands on one of them. The droid is confused as Anakin leans, guiding it away from the falls. The giant collector goes over the lava flow and disappears in the mist of sparks below.
They float toward one another and begin striking their sabers furiously. Anakin spins his saber around before bringing it across, only for Obi-Wan to block and parry. Anakin leans back to avoid being stabbed, then shoves the blade away before going for the mid-section. Obi-Wan barely manages to perform an under-arm block and uses Anakin's momentum to push off. They briefly float away from one another and there is a lull in the battle.
"I have failed you, Anakin. I was never able to teach you to think."
"When I became a Jedi, I had my reservations. I should have listened to my instincts."
"Anakin Skywalker was a hero. He saved lives. And now that man is gone, replaced by a Sithlord who kills his former allies."
"We must make sacrifices to do what's right. Isn't that what the Jedi teach?"
"If this is what you took away from that listen, then you are lost!"
"This is the end for you, My Master. I wish it were otherwise."
Anakin jumps and flips onto Obi-Wan's platform. They lock swords, but Anakin proves stronger and begins to overtake Obi-Wan. He grunts and bends back, nearly falling into lava. Up ahead, he spots an outcropping of magma rocks leading away from the lava. Obi-Wan twists, pushing Anakin off toward the esge of the platform where he nearly falls over. Obi-Wan then launches himself to the rocks and quickly climbs to a higher level. Anakin reaches his hand out, stopping the floating platform in place as it hovers above the lava. He glares at Obi-Wan, lightsaber in hand.
"It's over," Obi-Wan tells him, "I have the high ground."
"You underestimate me."
"Don't try it."
Anakin leaps, flipping in the air as he makes his way to his former master. Obi-Wan spins into an overhead swipe, chopping Anakin's arm clean off. Anakin loses his lightsaber and tumbles down the embankment, coming to a stop near the edge of the lava. There, his legs catch fire as he screams in agony. He struggles to pull himself up the embankment with his mechanical hand which is now visible as his clothes begin to burn up, including his glove. He keeps sliding down in the black sand as more of his body catches fire.
Obi-Wan is on the verge of tears as he shouts down, "You were the Chosen One! It was said that you would destroy the Sith, not join them. It was you who would bring balance to the Force, not leave it in darkness."
"I will destroy you! Do you hear me, Obi-Wan Kenobi? I swear it!"
"You were my brother, Anakin. I loved you."
He slides further into the lava river and ignites. Obi-Wan can watch no more and leaves as the screams die down. He runs back to Padme's ship a few minutes later and looks for Padme. She sits outside, clutching her throat, but is still alive. She looks up at him with tears in her eyes, "Obi-Wan? Is Anakin all right?" He looks at her sadly and does not answer. Soon, the ship flies away.
Nearby, Anakin crawls up the bank, his body smoking as he pulls himself along with his mechanical hand. As he makes his way to the cooler rocks, he reveals his legs have now burnt off. A shuttle flies overhead and lands. An Imperial shuttle closes its wings and settles on the highest of the Mustafar Landing Platforms. A platoon of troopers exit the craft, followed by Darth Sidious. Soon, he discovers what remains of Anakin and checks him out. He turns to the troopers, "He's still alive. Get a medical capsule, immediately." "Yes sir. Right away," the commander responds. Several of the clones rush off as Sidious puts his hand on ANAKIN's forehead.