When Twilight and Derpy arrived, Canterlot was in chaos.
The streets were clogged with ponies. Adults were shouting at one another. Foals were crying and clinging to their parents. Guards ran back and forth relaying orders and trying to calm the panicked citizens. Screams erupted from the crowd each time a beam attack struck the shield.
Though some distance away, the golem was clearly visible now. It fired its beam cannon at the city and the ponies attacking it on all sides. Smoke rose high into the air from the burning wreckage of whatever limited defensive armaments Canterlot had. A constant barrage of horn blasts from unicorn guards on the valley floor were little more than an annoyance to it, as were the swarms of Wonderbolts and Pegasus guards buzzing it.
Twilight led Derpy through the side streets towards the castle. They ducked in and out of alleyways, doorways, and other hiding places without any guards seeing them, but they were soon approaching the palace courtyard, and she knew that they would not be hidden for long.
They heard Thunder Chaser in the distance, shouting orders to the guards racing by him "Open up those bottlenecks! I don't care if you have to blast holes in the walls, get the citizens out of here! Send word to every city, town, or village in Equestria to stand by for evacuation at a moments notice; and tell Ponyville and Cloudsdale to clear out immediately, this thing's going after them after it gets done with us! AND WHERE THE HAY ARE THE PRINCESSES!?"
"Sir!" responded one guard, "Princess Cadence is refusing to leave Shining Armor's side! Nightmare Moon keeps ordering us away so we still can't get to Princess Celestia!"
Thunder Chaser started cursing, "I'm about ready to risk a court martial and carry them all out myself!"
Twilight spotted Shining Armor and Cadence. Even with his wife's magic and love assisting him, Shining Armor was straining to maintain the shield under the golem's barrage. He was caught in a catch-22, if he lowered the shield, the golem would sweep the city with it's beam attacks and massacre everyone, but keeping it up was preventing the inhabitants from escaping.
They all know they are about to die, thought Twilight. Most of Equestria’s top mages were concentrated in Canterlot. It were destroyed, there would be little that could be done to stop the golem. Every town and city would be leveled, and even Cloudsdale was not out of range of its beam cannon. Survivors would forever be on the run, trying to hide, starving as mana was drained from the land to power the golem. Equestria, and perhaps the entire world, was doomed if they failed to stop it here.
She looked again at the golem with her mage-sight. The rate of firing was slowing down as mana was diverted towards the two arms, each of them as large as the city itself. It was going to smash it's way through the shield. Twilight quickly scanned the monster and thought out her plan. The barrier protecting it's eyes was much more powerful, Derpy wouldn't be able to get enough speed to break through with the screwdriver and the golem was too tall for a kinetic spell to be effective, but if she were to get a boost from another pony...
Twilight saw her friends in the courtyard, looking very much out of place, and more than a little frightened. There was no other way, she had to get their help if they had any hope of surviving. Would they still trust her?
"Everyone! Listen!" Twilight called to them, "I know how we can stop it!"
They whirled around and ran to meet them. "Twilight," said Applejack, "We gotta get y'all outta here right..."
Rarity gasped as they drew close, "Twilight, what happened to you two!"
Twilight and Derpy would have been horrified if they could have seen themselves right then. Their legs were covered with deep cuts and bruises, and a trickle of blood from inside Twilight's hairline ran down her face.
"We don't have time, I know how we can beat the golem, but we are going to need your help if this is going to work."
"What?" said Applejack in astonishment.
"Derpy and I fought the prototype when we were in the Mist Continent."
"Hey, wait a sec," said Rainbow Dash, skeptically, "You and Derpy beat one of these things?!"
"YES, Yes we did! Now if you will just listen... "
"What are you doing here, traitors?!" bellowed Thunder Chaser, who along with several guards were pointing their weapons right at her and Derpy, "Are you trying to take advantage of the situation to get to the Princess?!"
"No Thunder Chaser, you've known me for years, you know I would never... "
"GUARDS! GET THESE PONIES OUT OF MY SIGHT BEFORE I KILL THEM MYSELF!"
Twilight screamed in frustration. "That's IT! I have HAD IT! FINE, YOU GOT ME! Blame me for everything! I stole your lunch money! I made it rain on your birthdays! Go ahead and lock me up forever, I don't care! But please, HELP ME SAVE EQUESTRIA!"
Everyone around her was silent. Applejack stepped up to Twilight and offered her support. "Alright Twi, ya'all tell us what ya want us ta do."
* * * *
Derpy thoroughly enjoyed being a projectile. She wanted Rainbow Dash to say something cool like "Derp missiles away!" (or not), but it was clear that R.D. was still pretty miffed about the whole broken guitar thing. If throwing her against a giant rock monster would help the process of forgiveness, it was worth it.
Applejack finished securing the screwdriver to Derpy's hooves with her rope, then Rainbow Dash picked her up and flew off.
Twilight wore the crown of the Element of Magic, and all of the other bearers wore their respective necklaces. All of them, with the exception of Rainbow Dash, were standing in a group behind several palace guards who were trying to hide their presence.
The plan was similar to the first: use Derpy's screwdriver to break the shield, then destroy the eyes. To get the boost that Derpy needed to bring down the stronger shield, Rainbow Dash would accelerate the two of them into a sonic rainboom, but there were problems with this. She had already shown that she could maintain that speed while carrying other ponies, as she had done when she saved three ponies at once during the Best Young Flyers competition, but she had never tried to accelerate up to that speed while carrying anyone. In addition, she was prevented by the shield from accelerating in a straight line, meaning she would have to circle around the inside until the shield was down. The final challenge for her was that after releasing Derpy, she would have to fly back to where Twilight and the others were so they could attack with the Elements of Harmony. Rainbow Dash had responded to the plan with her usual can-do attitude, but she and everyone else were still concerned. If only there was another way: if they lowered the shield too soon, the golem might begin attacking the city with it's beam cannon. They didn't have the time to get outside the shield, nor could they risk using the screwdriver for anything other than the monster's shield, as they didn't know how much energy it had left.
Shining Armor and Princess Cadence still did not know what was going on with the plan, nor did they know that Twilight was there. She didn't want any additional worries to distract them from maintaining the shield, if it went down before Rainbow Dash could reach the required speed, it was all over for everyone.
The monster was drawing close now, and its proximity increased their doubts. It was so huge that even standing on the valley floor it looked down on even the tallest towers in Canterlot, and dwarfed the whole city. Would the shield even hold against attacks from such a colossus? Only now did they start to realize how slim their chances really were.
It stopped, its fierce, glowing red eyes looking down on all of them. Slowly, deliberately, it's giant left arm started to swing back. The arm rose higher, touching the clouds high above them, reaching its highest point. Then the arm fell, faster and faster, down towards the shield."
"GET DOWN!!" some pony yelled.
Their ears exploded from the loud bang as the fist struck the shield. Shining Armor roared from the pain as mana flowed back into him. A shock wave flew past them, knocking several ponies out of the sky and almost blowing them over. Rainbow Dash flew out of control, losing all of her accumulated speed, and almost dropped Derpy. Cadence put all of her own magic into helping her husband manage the incredible pain and keep the shield up. Rainbow Dash recovered and began flying in broad circles around the city to regain her speed, but even as all of this was happening, the right arm was beginning to swing back.
The next blow fell, just as deliberately as the first. Again there was the loud bang, the shockwave, the cries of pain. Rainbow Dash recovered more quickly this time, keeping most of her accumulated speed, and kept flying. However, Shining Armor was getting weaker.
Derpy was beginning to feel useless again. At first, she had tried to help Rainbow Dash with the flying, but her own wing beats only interfered, and all she could do was maintain a gliding position. She was only a burden now to everyone, and she began to blame herself for everything that was going wrong.
On the ground, the situation was not much better. It took every bit of courage Fluttershy had to keep from bolting in terror. The anxiety and fear on Rarity and Applejack's faces were building. Only Pinkie spoke, "But, what did we do that was so wrong? Why would somepony want to hurt us like this?" Nobody answered, nobody could answer.
What affected Twilight the most was not the sight of the monster, nor the shockwaves. It was the sound of her brother in pain. She blamed herself for his suffering. If only she had come up with a better plan, one where she would not have to hurt him. She doubted every part of her plan now. Could the shield be too strong even for a sonic rainboom? Were the Elements of Harmony enough to destroy the bloodstones controlling the monster? Had Prometheus anticipated this plan? There was nothing to measure, no calculations she could make, it was only her gut feelings, how could she...
"You already know you can do this," said a voice that only she could hear. "Everypony here believes in you, and I believe in you too."
Twilight's courage began to come back. "Listen everyone," she told her friends, "we have never let Equestria down before, and we're not going to start today! We can do this!"
This was just what they needed. Each of them lost all of their fears and doubts, readying themselves for the attack.
The golem's left arm fell, and the shield shattered. Shining Armor fell to the ground at his wife's feet, unconscious and utterly spent. The final blow, the blow that would end them all along with their entire civilization, was already being readied.
There was an explosion of color as Rainbow Dash and Derpy rocketed into a sonic rainboom, and the two of them shot towards the golem's face. With one final push, Derpy was thrown at the monster, and Rainbow Dash made a wide back flip to fly back to her friends.
Derpy held the screwdriver in front of her and braced for the impact. The enormous face grew larger and larger until she hit the shield with tremendous force. The shield buckled and broke just as the screwdriver exploded in her hooves. Shaking the burning debris and rope away from her, she fell into a dive.
The golem's shield was down, but the right arm was still rising into the air.
Rainbow Dash flew towards her friends at high velocity, but there was another problem. She was too tired now to beat her wings to slow down, she was going to crash into them.
"Ah got er!" yelled Applejack as she shot forward into a gallop. She launched herself into the air and tackled Rainbow Dash. The two ponies tumbled violently end over end from the force of the impact. Pinkie Pie tackled them both to help slow them down, and the other three pony-piled on top of them. The arm continued to rise.
The Elements began to react, as if they knew how critical the moment was for all of Equestria. Mana surged into them and focused through Twilight. A broad, powerful rainbow of pure magical energy shot into the air, twisted, and slammed into the golem's face. The crystal eyes exploded with a deafening crack. The force of the rainbow pushed the golem backwards and away from the city. The monster itself began to break apart as it fell.
Derpy was still diving, trying to get enough speed, as the rocks began to fall. A shard the size of a building broke off and fell next to her. She ran down it to gain some more speed and pushed herself back into the dive. She weaved around falling boulders, past other giant shards, until at last she had sufficient speed. She pulled up, diving right under a falling boulder that almost blocked her way, and flew back to the safety of Canterlot.
The golem fell to the valley floor, causing a long roar and an incredible earthquake, but the sound was soon replaced by the cheers of every pony in Canterlot.
Twilight found herself caught in the best group hug of her life.
"Ahm so sorry Twilight!"
"We've been so beastly to you! Please forgive us!"
"I knew it! I knew you'd help us!"
"Please don't ever leave us again!"
"We love you too, Twilight!"
Derpy flew back, and Rainbow Dash pulled her into the hug as well. It felt so good to be back, to know that they were still friends, that she had earned their forgiveness.
Then Twilight thought about the voice she heard, the voice that had helped her to find her courage again. It was Darklight's voice. Twilight felt both relieved and afraid: relieved that he was there and still wanted to help her, afraid because he was very close to his objective.
There was something else as well. While the Elements of Harmony were firing, she thought that she had heard a voice speaking to her in her mind. It was Celestia's voice, and it was very faint.
Twilight... help... me.
"We aren't done yet!” Twilight said in a commanding tone. “Princess Celestia is in trouble and we have to get to her immediately! Darklight is somewhere nearby, look for a shadowy, black alicorn, he's difficult to see unless you look hard! Stop him, capture him, but DON'T kill him, Celestia needs to see who he really is! We saw Prometheus in the Crystal Caves, so expect him to show up anywhere at anytime, and don't take him on alone! We also saw Changelings in the caves, so Chrysalis is here too!"
Twilight's five friends and several guards scattered to look for the intruders, but Thunder Chaser remained behind with her and Derpy.
Twilight looked at the large and meticulously sharpened halberd, then she looked at its owner without a trace of fear. "If I try anything funny," she said evenly, "You have the power to stop me... but I am going to see Princess Celestia.
He nodded, and the three of them galloped into the castle.