Set somewhere in season 7. This fic counts on Amy and Rory being back with the Doctor and the Doctor knowing about the Question.
Disclaimer: I don't own Doctor Who. I also don't think this fic captures Rory's epic-ness enough.
"Do you ever remember it? 2,000 years, waiting for Amy? The Last Centurion?"
"Are you lying?"
"Course I'm lying."
"Course you are. Not the sort of thing anyone forgets."
"But I don't remember it all the time. It's like there's… a door in my head. I can keep it shut."
~ Season 6, Episode 2: Day of the Moon ~
It was a long span of time, to be alive and awake. Rory keeps the door in his head closed as often as he can. It's not that he doesn't like to remember, not really. It's more that he feels there is something there; a terrible secret, something that no one should ever know. Even he shouldn't know, at almost two thousand years of age. It is something that even he cannot afford to remember.
He would never tell this secret, of course, unless it was to save someone's life. So when he, Amy, and the Doctor land on a planet being invaded by Cybermen, the secret comes to life. He remembers that which no one should ever know.
Amy screams as the Doctor sets himself as the last line of defence between the married couple and the incoming Cyberman forces. Rory tries to drag Amy back to the TARDIS, but she refuses to leave her best friend.
"Go, Amy! I'll be fine, get back to the TARDIS!" The Doctor waves his sonic screwdriver and three Cybermen spark and shut down.
Seven more replace them. They shout "Delete! Delete!" in harsh, mechanical voices with metal eyes of no emotion. They march toward the trio, demands of assimilation and death floating through the air. The lead Cyberman speaks. "The Doctor will come with us. The Doctor will answer the question."
Amy almost trips backward as Rory grabs her hand and tugs her toward the TARDIS, which sits on a hill, now barely in sight. His wife screams and yells, but they reach the blue doors just as the Cybermen grab the Doctor and drag him away. She doesn't see him go.
Rory pulls his wife into the TARDIS despite her insistent kicking and screaming. Amy beats her fists weakly against his chest, then dissolves into a torrent of sobs. Rory holds her for a moment, then gently releases her and runs off to their bedroom. Amy is dumbfounded, but recognises the Roman uniform in his hands when he returns. He slips the not-quite-a-costume on, then belts the sword to his hip.
"I should start taking this with me," he mumbles, adjusting the armor. He peers at Amy, who watches him with a tear-streaked face. He walks over and embraces her once more. "I'm going to go get the Doctor."
"In that outfit?" she almost laughs, but chokes instead.
He pulls away and looks into her eyes. "The Doctor upgraded it, actually. The suit is some... metal alloy from the future. It can't be pierced by much of anything. Same with my sword. It can cut through any inferior metal." He doesn't comment on his shoes, which are definitely not the normal Roman type. Trainers, as it were. "Don't worry, I'll get him back."
Amy nods, then kisses him goodbye. "If you die, I'll kill you."
He smiles despite himself. "Deal."
Cutting across the empty fields to the Cyberman fortress is easier than he expected. Few Cybersoldiers are patrolling outside, which gives him ample opportunity to make his way in.
He isn't sure how to find the Doctor. The interior of the building is all silver metal, shiny and repetitive. He comes across many Cybermen in here, and stabs his sword through all of them. One of them almost crushes his left shoulder, but he sends its head rolling across the concrete floor. He travels through hallway after hallway, becoming more and more uneasy. Where was the Doctor?
"You great big ugly toasters! Get off of me!"
Rory peers around the next corner to find two of the metal machines dragging the Doctor away into what appeared to be a large room. He doesn't know what upgrading involves, exactly, only that it is unpleasant and quite deadly. He follows them as silently as he can, sword drawn. He knew how to fight as the Last Centurion and it hasn't left him now.
The two Cybermen drag the insult-shouting Doctor into a room and strap him down to a cold, unfeeling chair. He huffs and yells when one of them destroys his sonic screwdriver. "You do not need this implement."
"Yes I do!" he replies indignantly, shuffling in his chair. "That was important!"
One of the Cybermen pulls a device that Rory cannot see out of its mechanical arm. He had crept into the room after the two guards, following the Doctor closely the whole way. The room was filled with gas and exhaust fumes. He had coughed twice, but the soldiers hadn't heard him. He grips the hilt of his sword, ready to make the attack.
"You will answer the question, Doctor." The first Cyberman demands.
The second Cyberman, the one that Rory now noticed had a gun built into his silver arm, continues, "Answer the question or you will be deleted!"
"What question?" the Time Lord replied. Surely Cybermen had no knowledge of the question. Not his question, anyway. What use could they possibly have for the question?
"The question," the second Cyberman continues. The gun on his arm makes a noise as if it was loading and preparing to fire. Rory walks through the darkness of the room, creeping closer and closer to the robots. Only a few more seconds and he would be there.
"What question?" The Doctor repeats insistently.
"The oldest question. The first question," the first Cyberman speaks. "Doctor Who?"
Rory's feet freeze in mid-step. His head immediately begins to throb, like the worst migraine imaginable and he screws his eyes shut in pain. He clutches the sword with white knuckles and sways dangerously in the clouds of dark mist.
He feels it pushing against his consciousness. The door that he always keeps shut, the door that cannot be opened, lest he lose his current self to the Last Centurion. The metaphorical construct is pushing against his will, fighting for freedom. But Rory is fighting himself, and though he does not realise it, he is never going to win.
After a final shove, the door bursts open and all the memories of guarding Amy flood his mind, like a fob watch finally opened after so many long years. It fills him with a sense of relief, but in the dark recesses, a small bit of knowledge pushes to the forefront. It is responsible for this outburst, a terrifying gem of a secret. Something that he is not supposed to know.
The answer to the oldest question in the universe. Doctor Who?
Roranicus Pondicus, the Doctor had called him once. It seemed rather appropriate now.
He rushes forward, taking both of the Cybermen by surprise. Faster than the Doctor has ever seen his companion move, Roranicus beheads the robot with the gun and stabs the second through its metal heart. Both Cybermen fall, much to the Doctor's delight. He cheers and gestures at the controls to his left. "Rory the Roman! How glad am I to see you! The button's just over there. They broke my screwdriver, the fiends!" He pauses, noticing Rory's facial expression. "Rory?"
Roranicus stares at the Time Lord. He is so much more than just Rory now. Being alive in a collapsing universe had taught him to be wary. He had watched for the Doctor, those two thousand years. So many times the Pandorica had been moved and so many times, the Doctor in his various incarnations had been close by, but not quite there. Always passing by the box nonchalantly, as if it were unimportant. But that did not bother the Centurion.
He knew the Question. And he knows the Answer. Two thousand years had given him a glimpse of the Time Lord's life, but it was more than that. The Doctor was a Time Lord, by virtue a being that carved itself into the skin of the Universe with every step. That universe had collapsed in on itself, bringing with it every place that the Doctor had been and gone.
The Eye of the Storm was where it all came.
It had floated on starlight, drifting through the cosmos. Condensing more rapidly, erasing more and more things with every passing second. But as everyone knows, "Nothing is ever forgotten, not completely, and if something can be remembered, it can come back."
The Universe, as River had said once before, did not forget the Doctor. The pure essence of him was drawn to his beloved Earth and beloved humans. The Eye of the Storm. It found Roranicus, the companion of the Doctor. The Universe filled his mind and heart with the reality of that impossible man. Every person that he saved and every person that he allowed to die. Every footstep and breath that he took these long 900 years. He saw the Time Lord for exactly what he was.
The Last Centurion saw eternity.
Eternity. The true, piercing knowledge of the man that the Universe adored so much, it would not reveal his name to anyone but the most trustworthy. The one who could keep the secret.
He remembered. He knew. And he knows.
"Rory?" The Doctor watches him with intense concern. "Are you alright?"
"I'm fine, Doctor."
The Time Lord's eyebrows rise. He isn't sure that Rory realises he is speaking B.C. Latin. "Are you sure?"
Roranicus inclines his head slightly, both a sign of deference and personal status. He sees this Time Lord. He steps forward and leans in to speak quietly into the Doctor's ear.
When the Roman stands back, the Doctor is as pale as a sheet of paper. "How...?"
Roranicus feels the door recoiling, snapping back shut on itself. So he simply answers, "I was told by time."
Immediately, he lunges forward and hits the release button on the Doctor's restraints before crumpling to the floor. The Doctor jumps up and checks the human's vitals, relieved that he has only fainted. He awkwardly places Rory's sword back into its sheath, then feels relief flood him when Rory groans into consciousness.
"Rory! Wake up, we need to get back to the TARDIS!" He moves to pick the man up, then thinks better of it. Instead, he flits like a bug from machine to confusing machine in the room, re-routing gas lines and exhaust filters. Soon, the building is wired up like a bomb, with little to no time to get out. He reaches under Rory's arm and pulls the human to his feet. Rory has enough energy to semi-walk and they slowly make their way from the building.
Alarm bells sound and red lights flash as they find a cache of kidnapped people. The mixture of humans and aliens follow the Time Lord and his companion out of the building. They help Rory walk and soon, the human is able to carry himself with little assistance. Barely far enough away, the building explodes, taking every last Cyberman with it.
The crowd roars and cheers for their saviors. They follow the two back to the TARDIS, insisting on knowing just who these people are. Amy hears the noise and rushes out of the blue box, catapulting herself into Rory's arms. She eventually switches to the Doctor, who returns the embrace with much enthusiasm. Rory mentions something about wanting a cup of tea. Amy notices his tired face and rushes off to make it.
The Doctor waves goodbye to everyone and claps Rory on the back. "Good job, Rory." He follows after Amy, intent on fish fingers and custard for dinner.
Rory awkwardly weasels away from the crowd. He turns back toward the TARDIS, but a thin woman with brown hair walks forward and tugs on his sleeve. "Sir, excuse me?"
Rory blinks and turns back. "Um, yes?"
"That other man. He said his name was the Doctor. Doctor who?"
For half a moment, he almost decides to tell her. To let someone else in on the secret he now sort-of-knows, but not really. Instead, he lets a faint smile drift over his face and responds appropriately.
"Just the Doctor."