Disclaimer- I don't own Transformers Hasbro does.

Author note – Totally AU Megatron is Optimus' father and for the sake of the story The Fallen is a femme in this story.

Summary – Optimus falls in love with a femme who turns out to be his undoing placing him on a very dangerous situation with his Autobots and humans in the future.

A Calm before the Darkness falls

Chapter One

(On the battlefield)
Optimus was going after one of his father's warriors; when he was stopped in his tracks. Optimus watched as his father walked over toward him; he let his energon blades slide out. Optimus' battle mask snapped in place as he watched his father move closer.
"You are my son you WILL come home; even if I must DRAG you home myself!" Megatron roared, as he reached for his young son; who used his blades to defend himself.
Megatron snarled, and then reached once more for his disobeying son.
"OPTIMUS…!" Megatron shouted as he almost had the young mech. "You cannot hide who you are, Optimus; you are still my son and one day I will get you back." Megatron snarled as Optimus saw Starscream and Barricade walk up.
"You belong with me and one day; when you least expect it, I will get you back; even if I must take you by force." Megatron snarled approaching his son.
"You will NEVER be free from me; I will never let you go." Megatron snapped, as Optimus frowned and growling tried to attack his father; who easily blocked and pushed his son down onto the ground.
"Choose your battles wisely, Optimus; because THIS battle you will not win. I must continue to train you once I have you; you are too weak." Megatron said as Optimus snarled and charged his father; who easily caught the youth and twisted his wrist pushing him onto the ground. "As I said; you are weak, Optimus." Megatron said as he looked at his son. "Let's go, you're coming with me." Megatron snarled, as several Autobots came running up weapons drawn.
"Next time then, my son." Megatron replied transforming and taking off along with Starscream and Barricade.
Optimus looked up as two massive Autobots helped him up.
"Optimus, Falx wants to speak to you." the Autobot said as Optimus sighed.
He followed the two Autobots into not Falx's quarters but his quarters; and his optics locked with Falx's the second they entered the room. The expression on Falx's expression was one of anger; as Optimus sat down on the berth.
"Leave us…" Falx ordered as the two Autobots nodded and left.
Optimus knew what was coming now; and braced himself for it.
Pacing the floor before his 'leader's' berth, Falx fumed.
"I told you not to let him grab you Optimus," the silver femme said. "I TOLD YOU to use your rifle when you fought against Megatron, not your blades. I TOLD YOU he would seize any opportunity to drag you back home!"
She turned to face the sulking you Autobot on the berth.
"But NO! You 'know better' than to think a normal gunshot would take him down. You KNOW BETTER than a femme three times older than you!" Falx grit his dental plates. "Do you have anything to say, young mech?"
Optimus' optics blazed with both fury and embarrassment, he had thought he had done well. Why couldn't Falx be happy and proud for once; why was he constantly yelling at him.
"Falx, I wasn't offlined I... I thought I did rather well. I like using my blades." he muttered.
Optimus knew Falx was going to make more to do about this then was actually necessary. He wondered for a split second, if the two Autobots that retrieved him from the battlefield had told Falx about what had happened.
"What is the big deal anyway?" Optimus finally demanded of Falx.
"Big deal." Falx said. "Big deal!"
Falx closed the distance between them; before Optimus could even blink.
"YOU ARE OUR LEADER YOU PLATE HEAD! THERE IS NO WAR WITHOUT YOU!"
Falx pulled away and strode towards the window.
"If I had my way, you'd be locked in here whenever there's a battle going on! You'd be safe here, at base…"
The anger faded from the mech's form as he turned around.
"With me…." She added.
Optimus snarled.
"I know I am leader and Prime; I get it drummed in my processors constantly! Why won't you trust my instincts when I battle Megatron; why are you so afraid? I am careful not to get offlined..." Optimus paused and glanced at Falx. "I know he wants bring me back home; but that won't happen." Optimus stopped when he saw the strange look on Falx's face. "What else are you afraid of if Megatron got me and brought me back home?"
Falx didn't answer for a moment, thinking about the young bot before her the things she planned to thrust into Optimus' young life with no end in sight…
"You remember how the medics said that the changes in Megatron were externally caused, not internally?" Falx sighed and walked over to sit by Optimus.
Their optics locked.
"We never found the one responsible."
Optimus watched Falx, as his intakes cycled heavily.
"So, no one knows who did this to him? But that still doesn't explain your reasoning behind being so afraid; especially when I am good in battle." Optimus whispered sadly wanting to understand. "Is there something else I should know about Megatron that you're not telling me?"
Falx looked away, clutching the berth.
"I am a scholar, not a warrior, Optimus," she said, processor debating the best way to tell both the truth and a lie. "I specialized in ancient myth, as you know by now." Falx smiled at Optimus. "One of the things I learned about is…" The smile faded from his face. "The myth of the Fallen Prime; did I ever tell you that one?"
Optimus looked confused for a minute.
"No, you haven't I never heard of such a thing I thought all Primes were good and just."
Falx looked away, fighting the smirk. When she turned back, she was smiling sadly.
"That's where all this trouble started… People forgot there was such a thing…" The smile faded. "Originally, all the Primes were just and good. They were the leaders of Cybertron, and sent teams of Seekers out to find planets to harvest for energon. The only rule was…" Falx frowned. "If life in any form was shown to exist on the planet, it could not be harvested."
Optimus' optics widened Falx had his attention.
"No Prime would harm innocent life everyone knows that." Optimus said.
"And they didn't then," Falx said. "But there was one planet…One planet that the Seekers discovered that they had to let everyone see. This planet had… odd beings, the likes of which Cybertronians had never seen. The details vary from source to source, but what is always the same is that they had fur for helmets, weak flesh, and anatomy nearly identical to ours."
Optimus was curious now.
"These beings...Falx did the other Primes make contact and try to befriend them? They sound curious...fur on helmets? Weak flesh…...? …sounds fascinating. Can we ever see these beings, Falx? They sound so different from us." Optimus said.
Falx tried not to smirk.
"Yes, they made contact… They tried to befriend the race, but they were so…" she fought the snarl. "Primitive, killing each other, and animals, wearing skins to cover themselves against the elements. The Primes were enchanted by their behavior, their idiosyncrasies and quirks and odd choices in food." Falx frowned. "But one of them wasn't fooled by their sweet façade…"
Optimus' optics widened with interest.
"Really…? What did the prime do?"
Falx had Optimus' undivided attention completely he was entranced in the story she was telling him.
"They do sound a little cruel." Optimus said shivering at Falx's words repeating in his mind.
Perfect….
Falx placed his hand on Optimus'. She had Optimus right where she wanted him.
"This Prime… wasn't like the others. This prime had always been different, and the others had been uneasy around the prime. Yes, they adored that prime, but at the same time…" Falx lowered her head, remembering her brothers, the hurt looks when she revealed her intentions… "The Seekers had already brought the harvester to the planet before realizing that life existed on it. The Prime decided the best thing to do… The only way to free his brothers from the alien's control was to activate it and eliminate the race once and for all."
Optimus gave Falx a questioning look.
"But that seems unfair to the other Prime, he only wanted to help his brothers to free them from the alien life forms that were being so cruel." Optimus said as he tightened his grip on Falx' hand.
At Optimus' words, Falx immediately cringed. She'd gotten so deep into retelling her story she'd forgotten she was supposed to be warning Optimus about herself. She squeezed Optimus' hand and turned to him intently. "But the Prime was wrong." Falx said.
Optimus looked back up into Falx' optics.
"So, the prime was wrong to want to save his brothers from the aliens they encountered? But they sounded cruel to one another and the creatures that shared their world." Optimus said as he realized there was so much more to being a Prime than even he realized. "Will you tell me more, Falx?" Optimus asked, as he moved a little closer to Falx staring intently into the other' optics.
"Cruel?" Falx nodded. "Yes, they were cruel, but every race is in their infancy. Optimus, these aliens were young. They had just evolved into sentience; they didn't know what they were doing to each other. They killed each other and other beings to survive, because without nourishment and territory they would die. The Prime…" Falx hesitated. "The Prime's hate for them was unnecessary. Even if they had been a true threat to anything, the alien's feeble weapons wouldn't have been able to pierce the weakest of armor. They were harmless."
"Oh, so these beings are they still living? And the Prime you spoke of what happened to that prime?" Optimus said even though he said more to himself than Falx. "I wish I could have known at least one of the ancient Primes; sometimes it's lonely being a Prime. Sometimes it's such a burden that weighs heavy knowing I have to be like them make hard decisions."
For a moment, Falx's spark ached at Optimus words. In a rush unlike anything she often felt, Falx wanted to tell Optimus everything, tell the truth, apologize for her actions and claim him for her own… Primes belong only with Primes… Falx sighed and shoved that desire down.
"I know that at least one exists." Falx inhaled. "When that prime fell, the destructive Prime was sealed away and stored up in a room where the prime could never escape…" Falx looked Optimus in the optics. "After your father started acting oddly… I found a room like what was described in the myth, right down to the sarcophagus." Falx watched Optimus sadly. "It appeared… Megatron found it first."
Optimus' optics brightened. "My father…...? Does he have that sarcophagus now; what will happen if that Prime is brought back? Can he be brought back to the side of good at all, Falx? Optimus asked looking so hopeful not liking the idea a Prime could be evil.
"It appeared…" Falx hesitated. "The sarcophagus was already open when I got there. That much was quite obvious." Falx suddenly grabbed Optimus by the shoulders. "Listen to me Optimus. There is no doubt in my mind that your father is under the control of the Fallen. The only person that can defeat the Fallen is you, another Prime. If Megatron catches you…" Falx trailed off. "The Fallen will do unspeakable things to you if that prime gets a hold of you. It must never happen."
But it already did, and no one was the wiser Falx silently thought; as a sinister smile touched her lip plates one which eluded Optimus completely.