Outside of the Crystal Empire castle, trenches have been set up and turrets along with it. One of the turrets is a cylindrical shape which is utilized to defend against enemy foot soldiers. An earth pony opened the top hatch and manned the turret to be ready for anything. The other turret was dish looking.
Meanwhile back at the castle, Charming Thunder stared out of the window watching the soldiers preparing for battle. Cadence along with Applejack, Rarity, Rainbow Dash, Fluttershy, Pinkie Pie, and Shining Armor entered the room he was in and asked, "What's the plan?"
Charming Thunder turned and asked, "How are you feeling, Shining Armor?"
"I'm fine," Shining Armor replied.
"Good. The plan is to evacuated the whole town. I have already told the soldiers to spread the word to the crystal ponies to head to the transports that are just outside of the castle. We will hold off the enemy forces while they make their escape to Ponyville."
"And what are you going to do?" Rarity asked.
Charming Thunder took a long pause and said, "I will confront Twilight Sparkle here."
"And as for the rest of us?" Rainbow asked.
"Applejack and Shining Armor will help the ground forces hold off against whatever is coming. Fluttershy and Rarity will help the wounded. Rainbow Dash will lead the squadron of speeders we have brought with. And Pinkie....man the guns at the trenches."
"And what about my wife?" Shining Armor asked.
"She will evacuate with the others."
"Don't worry, honey." She then kissed Shining Armor on the cheek. "I'll be fine."
"Well you know what to do. Go." The group then left to head to their posts to prepare for battle.
---------------------
Applejack and Shining Armor were helping the soldiers carefully placing a blaster cannon inside trenches. Crystal ponies were in a single line at each transport to prepare the evacuation. Charming Thunder was in the throne room waiting for Twilight to enter until he felt a rumbling sound coming from outside. The soldiers outside heard it too. Even the pilots who were getting in their speeders. The soldiers at the trenches readied their weapons as the commander looked through his binoculars. In the distance, he saw four walkers approaching the kingdom. "Charming Thunder," the commander said on his comlink. "We have spotted walkers."
"Begin your attack," Charming Thunder replied.
"Yes, sir." The commander readied his weapon and headed inside the trench. The first transport lifted off and was being escorted by two ARC-170 starfighters to protect the transport at all times. The walkers then opened fire to the trenches as each transport took off. The speeders lead by Rainbow Dash have arrived to the battle and flew towards the walkers.
"Attack pattern delta," Rainbow Dash said. "Go now." The speeders then maneuvered past the walkers then swings around for another pass to distract the walkers. "That armor is too strong for blasters. Use your harpoon and tow cable on the legs in order to stop them." She then flew towards one of the walkers as the gunner positioned the rear gun to aim at the leg of the walker. "Activate harpoon." The gunner then fired the harpoon and it impacted on the leg of the walker. Her speeder then flew around the walkers legs in circles until it was time to detach the cable. The speeder then detached the cable and flew away from the walker as it collapses to the ground. The speeders then shot at the downed walker and it exploded into pieces.
Charming Thunder was staring out of the window watching the action when he saw a shuttle approaching the castle. It was Twilight's shuttle arriving to the castle. Rainbow Dash was covering a speeder trying to use its tow cable to take down a walker. "Watch that crossfire, boys," she said. The speeder she was protecting then exploded from the crossfire and she got hit by the crossfire. "Ah! I've been hit!" Sparks were flying everywhere in her cockpit as she crashed towards the ground. She then checked if the gunner was okay but he wasn't. She then unfastened her safety strap and pushed open the cockpit door open. The walker was in front of her getting closer and closer. She then grabbed her gear as fast as she could before the walker would crush her speeder. Once she got what she needed, she flew out of the cockpit and the walker stepped on the crashed speeder.
Charming Thunder saw the smoke coming from the speeder that crash landed in front of the walker as his comlink beeped. "What?" he asked.
"We can't take much more of this," Shining Armor said. "About half of the transports successfully escaped. What should we do?"
"Tell your forces to retreat and get to your transports."
"Ok." Shining Armor turned to his troops and yelled, "PREPARE TO RETREAT! PULL BACK! HEAD TO THE TRANSPORTS!"
Rainbow was behind the walker as she readied her grapple gun. She fired it under the walker and started to go up towards the bottom of the walker. She grabbed her pistol and shot the hatch that was close to her. She puts her weapon away and throws a thermal detonator inside the hatch. She detached the hook that was on her and fell to the ground. The walker started to explode from the inside as it was moving. Its head then blew up and collapsed side ways which also knocked down the other two walkers to the ground. She then flew to the transports and joined up with her friends. "Lets go," she said as the hatch closed. The transport then lifted off and headed straight back to Ponyville.
---------------------
Charming Thunder waited patiently for Twilight to enter the throne room. He then made an evil grin inside his helmet and he levitated off his helmet and placed it on the chair. "I've been waiting for you, princess," he said as he turned around to meet her.
"Where is my brother?!" she shouted. "WHAT HAVE YOU DONE WITH HIM?!"
"Oh, just a simple memory spell I casted on him. The same way I'm going to use it on YOU. You have allowed this...princess of the night to twist your mind until now...until now you have become the very thing I swore to destroy."
"Don't lecture me, Charming Thunder. You are not like Princess Celestia. I do not fear you. Soon I will end this rebellion and bring peace and justice to the New Lunar Republic."
"And my allegiance is to Celestia. To DEMOCRACY!"
"It doesn't matter anymore. If you are not with me, then you are my enemy."
Charming Thunder took a long pause to what Twilight said as he said, "Only Luna deals an absolute." He then grabbed his lightsaber to get ready for a duel. "You leave me no choice. I will do what I must."
"You will try, my old friend." Charming Thunder then activated his lightsaber as Twilight grabbed hers and did the same she then jumped towards him and started to strike to begin their sword fight. He blocked her first strike and tried to hit her leg. She blocked that attack and they started to move to another room. She then kicked Charming Thunder and he landed through the door to the hallway. They both then locked their sabers and Charming Thunder pushed her back. Their lightsaber strikes then hit the walls that were close to them. They entered the dinning room and Charming Thunder jumped on top of the table which was in the middle of the room. As he was about to strike, Twilight grabbed him by the neck and started chocking him. She lifted him off the surface of the table. Charming Thunder kicked her to get out of her grasp and she dropped her lightsaber. She then kicked him and he landed on the floor. He got up and blocked her punch attack and kicked her to the ground. He then levitated his lightsaber and grabbed it. Twilight did the same and blocked Charming Thunders strike. She got back up and kept on striking him as he blocked those strikes. They both then started to twirl their swords and locked their blades again. When they both collided back, they both charged up their horns and fired a blast at each other. The beam of both Twilight's and Charming Thunder's impacted as they both fight to win the clash. Charming Thunder won the clash as Twilight was pushed to the wall. Charming Thunder jumped into the air and tried to slice her. She dodged and the attack hits the wall instead. They both exited the room and headed to the outside of the castle. Twilight attacked as they both left the castle. Charming Thunder jumped up to the roof of a house as Twilight flew to the roof. Charming Thunder was the first to strike when Twilight landed on the roof. She then punched him in the face and when she was about to strike, he grabbed her hoof that was holding the lightsaber. He then pushed her back real hard and when he got back up, they both locked their blades.
---------------------
The LAAT/i transport headed back to the Crystal Empire to check on what Charming Thunder is doing. "I'm worried about my brother," Cadence said. "I'm just afraid that he would get hurt or get captured."
"I see them," the pilot said. "They are dueling on the roof."
"Get us closer," Rarity said.
"Yes, ma'am." The transport then flew to the location of the fight to get a closer look of what is going on and hope that Charming Thunder is hanging in there during the fight.
---------------------
Twilight tried to strike Charming Thunder's head but he blocked that strike. He then pushed her back and the strikes her left arm but she blocked it. They both then just stood there staring at each other. Charming Thunder then levitated some rocks and started to throw them at her. She dodged the first rock by moving left and dodged the second rock by jumping over it. He then started blocking Twilight's attacks as she used her anger to try to kill him. They both then locked their blades and Twilight said, "Any last words before I kill you?"
"Yeah," Charming Thunder said as his horn was glowing. "Duck." Twilight looked next to her and a rock hits her and she fell off of the roof. Her lightsaber was now out of her hoof and he jumped down off the roof and walked over to the downed Twilight who was crawling to her lightsaber. His horn then glowed as he said, "You underestimate my power." His horn then impacted on her forehead and Twilight then started screaming. Once it was done, she was knocked out and he heard a transport landing to the ground behind him but didn't bother to look behind him. He instead just stared at his best friend lying on the floor and silently saying, "I'm sorry. I'm so so so sorry, my love." He then sheds some tears when Cadence placed a hoof on his shoulder and embraced a hug to him. The fight was over. He then walked with his sister as Rarity carried Twilight to the ship. Once they were on board, the ships doors closed and lifted off to set their course to Ponyville.