And no one on the outside may enter its boundaries, save for the length of a dream, or a flash of an inspiration.*
Night's end does little to bring light upon the crumbled ruins of the Old Equestria city. The clouds above, and the flocks who tend them, keep the wasteland in shadow even as Celestia's light rises on a new day.
Alone, among the shattered remains of a once lively city, stands a tower. There it has stood for a century, having watched its brothers fall around it, the lone survivor among its burned kin.
Atop this tower stands a lone figure, a sentinel, clad in salvaged armor once used by the Equestrian riot police. The figure wears two masks which match the armor: One mask is worn over the face, well-maintained and kept clean, looking as if it were freshly issued that very morning. The other mask is worn on the back of the head. Beaten, scarred, and cracked, the mask has long ago been broken beyond repair. Still, it holds together.
The sentinel's heavy cloak whips around the stoic figure's form as a strong gust of wind blows across the rooftop. Down below, a few shadows begin to move. The sentinel spots them and looks closer through the scope of a high power rifle.
On the city's edge, a small group of three ponies make their way into the ruins. They're young, still, but the wasteland has aged them prematurely. The eldest, a unicorn, bears the scars of a lifetime spent fighting over meager scraps. He carries an old rifle, scarred like him, though these scars take the shape of letters on the wooden stock: "Old Painless." The sentinel focuses on the unicorn's left foreleg: It's crudely splinted, though not to set a fracture. Looking behind the splint, the sentinel sees that the nerves to that leg were cut by an injury long ago, leaving him with an unsteady gait. Still, he holds together.
His legs wobble like jelly, threatening to shatter from fatigue. Time, wind, and rain gnaw at his flesh, working to strip away whatever remains of the life that once burned inside him.
The other two ponies have similarly battered conditions, but the sentinel isn't interested in them. Looking ahead of them, their futures end soon. A doorway awaits them as the trio climb their way through the city ruins. The doorway stands by itself, the walls around it having been lost to history, little more than lines on some long lost blueprint now. The younger two ponies lead ahead of their lame companion and approach the doorway. The sentinel looks ahead of them to the doorway and waits.
A shot cries out in the early morning, echoing around the ruins. Two ponies collapse as they pass through the doorway. The air is still and silent for a moment after that. The eldest pony has vanished from sight. A single brass casing clatters to the rooftop as the sentinel chambers another round.
The sentinel is knocked back by a hard kick in the chest. The echoes of another shot reach the rooftop a second later. The air is calm. Then the sentinel stands back up. Looking through the scope again, the lame pony is hobbling over to where his companions lay dead, the rifle slung over his shoulders, still smoking from his return fire.
His brothers already lie in jumbled, gruesome heaps. But still, he hangs on.
A third report sends the unicorn back into cover as the round grazes his horn. The wind whispers, "You are not ready to cross that threshold."
For a moment, the unicorn is allowed a glimpse inside the tower. He looks upon the sentinel there; a dark figure with intents unknown, perhaps simply crazy, the unicorn supposes—but only briefly—as he brings his rifle to bear, and looks at that dark silhouette through his scope. He fires without hesitation; the only consequence he looks for is the end of his adversary.
He looks, but does not see. He does not see the sentinel as he scans the skyline, because the sentinel sees him, sees what he has been, what he will be. Many others have tried to challenge the sentinel before, and all have fallen; only the sentinel remains standing atop that lone tower.
It's not pride that holds him upright—there is no beauty left in him; age and hardship have withered his elegant features down to bone. He stands all alone, swaying meekly in the wind, because he must.
A glint of light appears amid the rubble, and the sentinel ducks behind the tower's parapet before the scavenger sees anything. Moving to a new position, out of the scavenger's line of sight, the sentinel takes another shot, shattering pieces of the concrete wall beside the unicorn's head, peppering his face with flecks of cement, lead, and copper.
Again, the unicorn looks without seeing. For the length of a dream, he looks up at the sentinel atop the tower, rising up over the ledge. The wind howls, throwing up dust and whipping the sentinel's cloak into a broad silhouette. A single, well-aimed shot would send a bullet ripping through the figure's neck, shattering spine, and rending veins and sinew alike.
But the unicorn cannot see that. The tower's doorway is not for him to cross, and he must retreat deeper within the hollow carcasses of the tower's fallen brothers while the sentinel still stands watch over the ruins.
Having lost sight of the pony, the sentinel moves around to a flanking position, gliding through the familiar ruins with practiced ease, and looks down the rifle's scope once more. There's a faint, pale blue glow showing from around a corner. Looking behind the glow, the sentinel sees the unicorn taking out his journal and a pencil to sketch out a map of the ruins from memory.
The rifle fires; a split second later, that pencil shatters into pieces. Crosshairs follow the pony as he crawls on his belly and drags the journal in his teeth, retreating deeper into cover. He dares not use his magic again. The sentinel looks forward to when he does.
He feels the ground below him beckoning, pleading to him to lay down and rest his tired bones, but he still has the strength left to say no. When his creators brought him into the world, they blessed every beam, fibre, and pane of him with the same, all-important purpose: To stand.
The day passes on, as does the next. All the while, through the rifle's scope, the sentinel looks ahead of the weary pony down below. Several times, he tries to break for the city's outskirts to attempt an escape. Each time, he finds a bullet at his hooves, driving him back into cover.
Celestia's light grows dim. The wind gusts, making the lone tower creak and sway. The tower whispers meekly, but only his sentinel can hear: "Your end is coming."
The sentinel atop the tower keeps a watchful eye over the ruins. Always looking ahead of the poor wretch down there; herding him deeper into the ruins with every shot. He's trapped now inside a collapsed storefront. Ahead of him, there is now only certainty. The sentinel has shown him his own future, and he is finally ready to step through that doorway.
The scope stays focused on the open window on the second story of that storefront. A small shadow appears briefly; then, it explodes into a dark stain across the concrete wall. The final crack of gunfire echoes through the air as the wind calms.
And so, through time, pain, and sorrow, he holds his head aloft.
Rising up on shaky, tired legs, the sentinel looks out over the wastelands, looking ahead as the night begins, blanketing the city ruins in darkness. The lone tower stands still, waiting for his day.
Author's Note
*Line quoted from the move The Flight of Dragons (1982). Go watch it.
