This is an old idea that I finally gave life. As a writer, the notion of a 9 million year old being dying for a creature that would live 0.00001 of its lifespan is a difficult narrative to grasp. I also don't see many fanfics from Optimus's perspective. Here, I have tried to explore the 'why.'

Samuel James Witwicky will live only a blink compared to the age of Cybertronians. His life is nothing but a blip in the course of their long memories. Optimus's arrival on earth had been an accident of fate. One that he had never intended. In his search to recover the AllSpark, he had explored many worlds, worlds teeming with life and worlds devoid of even a spark of it. Never had he seen a world so resplendent as the planet earth. Not even Cybertron in her glory had boasted so flourishing an eco-system.

The small near-forgotten part of him that had once been a scientist marveled at earth's wonders. And at the center of those wonders sat a single human. A child, really. The first human to whom he had revealed himself upon arriving planetside. The first of this strange species with whom he had truly conversed.

The boy, Sam, had been bold. Bolder than he should have been for a creature so small and delicate. He had trusted Optimus without a thought. Perhaps, foolishly. And yet, Sam, a human child, had risked his life in defense of the Autobots, in defense of the AllSpark, for a war and a cause that had existed before his ancestors.

It would have been easy to dismiss humankind as lesser beings, inferior creatures to be subjugated and exploited. Their lives were so short and their bodies so fragile, but Sam had been enough to prove that they were not so different; they loved and laughed and hated and grieved just like the Cybertronians. To dismiss their sentience as insignificant solely because of their size would be a grave error.

The boy had spared him. Moved by undue loyalty and compassion, Sam had disobeyed Optimus's order to destroy the AllSpark in the well of his chest. Sam had created a third option, one that not even Optimus had considered, by charging straight for the Decepticon leader and plunging the deadly cube into Megatron's spark instead. That day, Sam managed to touch something deep inside the old Prime's spark, something that was still gentle inside his tired soul.

Unlike Optimus, Sam was still guileless and innocent, untainted by eyes that had grown tarnished by eons of death and betrayal. Perhaps, in some ways, Optimus saw the soul he had once had reflected in the boy's idealism. More than that, Sam also reminded him of Bumblebee, and how the young bot had once been before war had hardened him.

The desire for offspring permeated all beings and Optimus was certainly not immune. He, too, thought of legacy, and of what he would leave behind when, at last, his spark burnt out. But Optimus had never had a sparkling.

The war had started when he had come of age, and it had seemed foolish, irresponsible, even, to divide his attention when the Autobots had needed him most.

As the youngest of his soldiers, Bumblebee had come the closest to filling that ache. It was no small surprise to Optimus that Bumblebee became so fond of Sam. The two were very alike, and the parallels nurtured a fondness that the Prime could not help but acknowledge.

Even through his years with NEST, the thought of Sam and the life he would lead was a pleasant one that eased the sorrow that often filled Optimus's processor. Being the last of a long and noble lineage, one of very few Cybertronians remaining, was a burden for which none could have prepared. Still, to know that their sacrifices allowed Sam to live in peace, along with all the rest of humanity, it was enough to ease the pain of his grief.

It was strange how little Sam understood his significance or how much of Optimus's faith in humanity rested on the earnestness of an adolescent boy. Never was that more clear than during their meeting in that fateful cemetery when Optimus had all but pled for him to speak for their cause to counter the misguided dogmatism of Director Theodore Galloway.

"You're Optimus Prime," Sam had said, "you don't need me."

Everyone seemed to think that being a Prime changed something. In truth, it changed everything and nothing at all. He was, at his core, still a Cybertronian scientist, only now, both worlds, human and Autobot, looked to him for answers he could not possibly provide.

As was often the way of sparklings, Sam had not understood and could not fathom the role he played in this grand drama and the power he held within his small organic frame. If anyone could have convinced the human government of its folly, it would have been Sam.

As Sam walked away, the Autobot leader held back the sudden desire to lecture the youth and scold him for his blindness. Optimus knew it would have done nothing but further convince the boy of his opinion. He would not take the boy's freedom. It was Sam's right to deny him, and he would not cheapen that right by disregarding it when it suited him. Even so, Optimus had been angry with him then because, for the first time, Sam had disappointed him. The Prime had left their meeting with a heavy spark and an uncertain future, with no solution to offer his Autobots.

Optimus may have been angry, but when word came that Sam had been taken, all he had felt was a strange and sudden fear. As he'd raced toward the Decepticon's hideout, Optimus had been filled with a possessive rage, one that he had almost forgotten; whichever Decepticon had done this would die for it.

After he had rescued Sam and fled their pursuers, it had not occurred to him that he was trapped until he had found himself alone, staring down three heavily armed and armored Decepticons in the midst of those lonely woods. The odds were not favorable, even for a Prime. The Decepticons taunted him with their advantage as they told him to let the boy die, whispering that Sam's short life was not worth the millennia-long life of a Cybertronian, not worth the resurrection of Cybertron.

At one time, he might have agreed with them, but Cybertron was gone.

As he looked at Sam's terrified face, he saw the fragile flickering of the future. Humanity was now Cybertron's future. Only Cybertron's ideals lived on, and Optimus would not see those ideals extinguished. That would always be his legacy.

"You'll never stop at one. I'll take you all on!"

Optimus fought bravely, and he fought savagely, fueled by unfamiliar fury. They had taken a soul under his protection, and he relished in making them pay for that mistake.

Distracted by the heat of battle, he never even felt the blade go through his back. Only found himself hoisted in the air before a shot from Megatron's cannon tore through his bleeding chest.

As he fell, the world dimmed. Growing fainter and fainter. The last thing he saw was Sam's face, twisted up in horror.

Run, he tries to beg the boy, run…

The future is in your hands now, Sam. You are my legacy…

"Run, Sam…ru—"

This story came to me as an attempt to justify Optimus's actions in RotF upon re-watch as an adult. Reviews do not require registration and I would love feedback.