The final flashback of the story, and we finally see Celestia booting Dawn out of school after her assault on Twilight. The Princess does, however, try to soften the blow a bit:
Joyous hope warred with grief in the breast of Breaking Dawn, Celestia's words so addling her wits she could only stammer, "You mean, if I prove myself to you, then I can come back?"
"In a manner of speaking, yes."
Back in the present, Luna again comforts Celestia over the situation and her perceived culpability as the latter retires for the night. Luna then enters the dream world to search for Dawn, because no way is there a problem with leaving every single princess dead to the world during such an unstable time.
Dawn herself is just waking up, and tells Razor about a particularly bizarre dream experience, of herself as an attention-drawing statue in the middle of Ponyville. Dawn mulls over its possible significance, before getting to the heart of her funk:
Razor Wind was silent, recognising that these were things that Dawn needed to say.
"All these years I imagined that the only way she could have stolen everything from me was if she was a monster. A villain, who cackled as she destroyed me. But that mare that I left back there...Celestia help me I'm not sure if I was ever that nice. I mean, what could have been her last night alive and she spent it talking about some days she spent hanging out with her friends, doing nothing of any consequence, just relaxing. I don't think I was ever that free from ambition. Maybe that was what Princess Celestia saw in her heart that wasn't in mine."
Razor Wind's voice was nervous, almost scared, "What are you trying to say Dawny?"
"I think she's a better pony that I am," Dawn murmured, resting her forehead against the mirror. "I think she might deserve to be the hero more than I do. I think she might even deserve to mount me as a statue in her hometown for everyone to admire her triumph, like in my dream."
"But you still tied her up, right?"
Dawn sniggered, "Yeah, I did. I have to know, for certain. I have to at least try, then I can know for sure if I have what it takes, if I ever did. I need to talk to the Princess. I need to know. I've worked so long and hard to get this chance, I just have to take it."
Lord Mathos contacts the Grevyian Emperor himself, who despite distancing himself from the operation turns out to have been the true instigator. In fact, Mathos himself only got forced into the job due to being a very minor noble- and having his family placed more or less under royal hostagedom- and his shadowy manipulator cred goes straight down the tubes. If nothing else, though, it emphasizes the true scope of the conflict. Mathos orders Jugurtha to eliminate Breaking Dawn after the princesses are taken care of- via a pair of ancient bridles which were supposedly used to harness alicorns to pull the celestial bodies in zebra prehistory- despite the latter's reluctance to so repay her assistance.
Luna is woken by her guards as the Grevyian attack begins and barely escapes being bridled (though of course Celestia wasn't so fortunate), calling her guard to her and attempting to rally the city for a counterattack. She's not the only one, as Dawn and her friends embark on what's left of her plan, kicking zebra flank and rescuing a group of prisoners, finally earning some street cred:
Some of the ponies muttered at that. A lithe limbed unicorn mare asked, "What can we do? We are not warriors?"
"Are you not possessed of legs and hooves?" Dawn asked. "Are your hearts not stout, your spirits not possessed of the spirit of harmony and friendship? Are you not the heirs of those brave ponies who dared the frozen wilds to win new homes and new lands for themselves and for their children? Are we not ponies proud and bold, equal to any challenge that magic, nature or other races may pose to us? The greatest weapon in this battle is not the zebra's spear, nor his shield of hippo hide, but our valour undimmed and bonds of comradeship unbreakable. Take heart, stand fast, and they shall be as chaff before our mighty wind!
"Is there anypony here who does not love Celestia? Is there anypony here who does not love this city which has raised us all? Is there anypony here who would see the greatness of Equestria cast down and replaced with Grevyian chains? If the answer is neigh, then fight! Fight for Princess Celestia, fight for Canterlot, fight for Equestria and all these things we love about this land.
"These zebras think us soft. They think us weak. They think that because we live in cities, because we have no fear of nature, because we do not live in constant struggle, because we settle our disputes without recourse to force, that we are soft and cowardly. Shall we prove them right by cowering in the streets, or shall we show these Grevyians that a pony may be as brave as any zebra when her cause be just?"
The ponies began to cheer, a great rolling wave moving from the centre of the square out to the edges.
"We'll show those zebras what we're made of!"
"We'll fight for home and Princess Celestia!"
"We're with you Breaking Dawn!"
"Breaking Dawn! Breaking Dawn!" they cried her name all over the square, hooves pounding upon the ground or pumping upwards into the air. Soon every pony from the oldest bearded stallion to the youngest filly was yelling her name, proclaiming her their hope, their saviour, their champion.
Did they ever cheer you so, Twilight Sparkle? Dawn asked, as she felt such pride stirring in her breast it moved her to glad tears. This must be how Princess Celestia feels every day.
As they cheered, a red pegasus leapt up onto the plinth beside her and kissed her twice upon each cheek, before flying away and vanishing into the press.
Dawn's green eyes widened, she took a step backward in shock. My dream. This is just like my dream. She was in Canterlot instead of Ponyville, but everything else was correct: the great crowd massed in admiration of her, all eyes turned on Breaking Dawn, and the pegasus had kissed her. She could almost hear the bells of fate tolling in the distance.
"Dawny?" Razor fluttered down beside her. "Dawny, are you okay?"
Dawn blinked, managing to smile, "Yes, yes I'm fine." Because really, how could she doubt now that her dream had been an omen of success. They really were cheering for her. That kiss had been the seal upon her triumphant. Success is assured now. Destiny is upon my side.
"Everypony, let's go," Dawn yelled. "And let our cry be 'Canterlot! Celestia and Canterlot!'"
"Canterlot! Celestia and Canterlot!" the crowd chorussed, and Dawn let them whooping and hollering into battle to retake their city from the foe.
And as they followed her through the streets, saving hapless ponies, rescuing captured children, assisting groups of stranded guardsponies, on this night of madness and misrule Breaking Dawn became the hero.
Lancer finally fights his way back to Shining Armor's cell and releases his restored captain. A lot more pretty neat flank-kicking ensues, but the only thing to stick out here is the inevitable appearance of Flash Sentry, before they and a few other guards break open the barracks where the others were barricaded, even as Twilight, Applejack and Spike do the same for their friends at Twilight's palace (and Twilight fully reconciles with them all).
Twilight leads her friends to the hospital and blows her way into Cadance's room, convincing Cadance to let her into her head, encountering a manifestation of the poison:
Twilight frowned. Cadance was standing before her. A transparent, almost ghostly Cadance, more drab of mane and seeming less beautiful, less vivacious. Less kind, too. Looking into her eyes, there was none of that spark of devotion to others that had made Cadance who she was. This was a Cadance in physical form only, inside she was something else.
"What are you?" Twilight asked.
"I am Me," the thing said falsely. "Me as I will become. As I acquire more memories, so I create a new identity for herself. That identity is me. Soon I will be complete, and then I can take over this body."
"No," Twilight snarled. "She doesn't belong to you. I won't let you have her."
"I am her," the not-Cadance insisted. "I am a pony, just as she is. Only I'm not trapped. Someone has to be this pony."
"I'm going to save Cadance," Twilight growled. "I'm going to get her back from there."
"Why bother, when I'm here?" asked the not-Cadance. "How can you destroy me, just for her sake? Aren't I a pony too? Don't I matter?"
"No." Twilight said coldly. "You're not a pony. You're just amnesia and a few memories of a padded cell. You aren't real. You're nothing compared to the real Cadance. Now get out of my way."
"No," not-Cadance yelled. "I'm here now. I belong here. I won't let you destroy me!"
She sprang at Twilight, but Twilight teleported behind her at the mouth of one of the tubes down to the heart.
"No," not-Cadance cried. "No, please, no!"
Twilight didn't listen. She just leapt.
