Disclaimer: I do not own Transformers. I do own a very cute cat, so she'll have to do for now.

A/N: Due to the possible confusion with Unicron controlling Alexis, I will keep using 'Alexis' instead of 'Unicron', if only for my sanity (and because, well, it's her body doing/saying stuff).

Chapter 20

"Unicron."

"In the flesh," Alexis said. Or Unicron said. Sam was utterly confused.

"How-"

"The minute the girl touched my spark I was in control. I often take over the minds of my minions by exposing them directly to my spark. That is how I took control of Starscream when he hid on my former body. He thought it was just an asteroid," Alexis chuckled. "I wanted to posses your body, but your various encounters with the Allspark and Matrix seem to have left you immune. Indeed, it's hard enough controlling humans as it is."

Sam could hardly believe his eyes or ears. This could not be happening.

"What is going on?" he demanded.

"I need a new body, it's as simple as that."

"So you picked my cousin? A five foot tall girl?"

"This is just a transitional form until I get Primus' body."

"Primus-? How are you even alive?" Sam asked. Alexis held up the orb in her hand.

"Back in my old body, I only pretended that the girl had destroyed my spark. As long as my spark is intact, I cannot die. And in a few moments, you shall help me take my new form."

"Primus' body? Where is it?"

"Sam, we're on it."

"But we're on Cybertron!"

"In the beginning," Alexis said, ignoring Sam's outburst, "Two brothers were formed by the Allspark. One was Primus the creator. The other was Unicron the destroyer. After eons of battles, we were both locked away in asteroids, unable to continue our fight for dominance. Primus then set to work creating the Transformers while I destroyed what worlds I could. Although we started out equal in size and strength, the Transformers added more and more to Primus, renaming him Cybertron as they forgot their origins."

"So you want to become Cybertron? It's a dead planet…"

"Only somewhat, Samuel. Primus is not dead, not yet. But he is sick. Now is my only chance to strike. With my brother in this weakened state from the Transformer civil war, he is vulnerable to my takeover. Once I have control, I will be unstoppable. This new body will be more than twice the size of my old one. None shall challenge me and the universe will finally end."

"Why are you telling me this?"

"Because you have a part to play in this. I need you to open the door. You, chosen by the Allspark to be the champion of the Matrix of Leadership, can open the Well of All Sparks. It is, as you humans say, your destiny. Although I am a little disappointed." Alexis shook her head. "I thought that you'd be a more worthy adversary. I worked so hard to ensure my plan went through without a hitch, the entire time fearing that you would discover the truth. Yet it seems my fears were misguided. You're no threat at all."

"I'd watch what you say. I'm not the 100 pound girl," Sam challenged.

"You plan on fighting me? Now, Sam," Alexis warned, "I might be in a weak organic body, but any harm you bring to me will only hurt her."

"How long?" Sam asked suddenly. "How long have you controlled her body?"

"Only since she took my spark." Alexis studied the small orb in her hands, like a jeweler examining a diamond. "The cerebro-strip was only controlling her when I needed to intervene. However, it proved far more useful than just getting me close to you. It allowed me to plant images in her mind. Your Autobots thought it was merely an aftereffect. Little did they know that I had planted a subliminal message, so that even after the strip was removed she would fulfill her duty by bringing you to my spark."

"Well, you're going to get out of her mind right now," Sam said, approaching the possessed girl.

In response, Alexis removed a small, silver object from her pocket with her free hand. Sam recognized it as the thing she had been fiddling around with before. Pressing a button, the small thing transformed, revealing a sharp, long knife. This stopped Sam. Unicron was going to kill him!

For once, Sam was glad to have paid attention to Simmons. "I think you forgot a little detail: these suits are tear proof. That knife won't get through the fabric."

"Who said I would use it against you?" With that, Alexis pressed the knife against her own neck. "If you take another step your cousin dies."

Sam grimaced but acquiesced. "What do you want me to do?"

"Fulfill your destiny and open this door."

"Um, how?"

Alexis rolled her eyes. "Place your hands on the seal. Order it to open."

Sam considered making a joke but he bit his tongue. With that knife pressed against Alexis' neck, he couldn't take any risks. His mind raced as he joined the girl on the circle. If he got the thing to open (and that was a big if) it might distract Unicron enough that Sam could tackle them to the ground. Then, he would just wait until Optimus or Bumblebee found them and destroyed Unicron's spark for real. Sam then realized the flaw to his plan: with the Decepticons attacking, it might be a while before any Autobots could help. He looked back at Mikaela, who had stayed against the wall during the entire exchange. Hopefully she would help him to keep his cousin down. Seeming to sense his idea, Mikaela followed him onto the circle.

Purple eyes watched with great anticipation. Sam studied the seal beneath his feet. Right in the center was a blank square surrounded by thousands of tiles. It formed an unending chain of glyphs, the same that had haunted Sam the days preceding the Fallen's attack on Earth. The symbols had been completely removed when he had recovered the Matrix of Leadership, but the sight of the blank square caused thousands of them to flash before his eyes again. Unable to control his movements, Sam began tracing the figures onto the blank square, forming the glyphs that would unlock the seal on the Well of All Sparks.

With a resounding crack, a split divided the circle. Sam blinked away the images in his mind and saw that the seal was literally breaking apart. He pulled Mikaela off of the crumbling structure and looked at the stairway that was revealed. To his surprise, the steps were close together, as if meant for humans legs rather than Transformers'.

Alexis smiled and lowered her knife. Holding up the spark, she gave Sam a jaunty wave. "Thanks for your help, Sam."

"You think I'm not going to let you go without a fight? I don't think my cousin will mind a few bruises if it means stopping you."

"I'm not going to fight you, Sam," Alexis said, raising her hands in mock defeat. "But she will."

That was when Mikaela punched Sam in the side of the face. Caught off guard, Sam fell to the floor. Looking up at his girlfriend, he was shocked to see that Mikaela's face was void of all emotion. Then Sam remembered what Unicron had said earlier.

It's hard enough controlling humans as it is. Humans, as in plural. Unicron was controlling both his cousin and his girlfriend.

"Mikaela," Sam said weakly. As anger grew within him, he wondered just how long Unicron had been controlling his girlfriend. He figured Unicron had probably taken her over when they entered the chamber, as she had been acting normal throughout the return trip to Cybertron…Rather, the return to Primus, if Unicron was speaking the truth.

"Have fun, Sam. And Mikaela," Alexis turned to face her minion. "Feel free to kill him." She dropped the knife she'd been holding, kicking it towards Mikaela.

As the possessed Witwicky started down the steps, Mikaela ran at Sam. He tried to defend himself, but she was too strong, too furious. He didn't want to hurt her, but her orders were to see him dead.

"Mikaela, it's me! Unicron's controlling you! Fight it!" Mikaela ignored his pleas, only kicking him hard in the gut. "Please! You don't like it when I die!"

There was a sudden pounding at the door. Sam prayed that it was an Autobot coming to his rescue. He didn't know how much longer he could keep Mikaela at bay.

"You love me, remember? You told me that to keep me alive! Don't-"

Mikaela slowed her assault. Whether or not it was from his argument's was unclear: she might have been savoring the impending kill.

"Mikaela, I love you. Please," Sam locked eyes with his mind-controlled girlfriend. She started shaking, and for a moment it looked like she might have gained control again. The pounding at the door grew louder. A few more seconds and reinforcements would arrive-

"Die!" Mikaela screamed, picking up the knife Alexis dropped.

There was an explosion and a flash of yellow filled Sam's vision.

"Bumblebee, grab Mikaela!"

The yellow bot did as he was told, restraining the struggling girl with ease. His optics appeared confused, so Sam quickly explained it.

"She's being controlled by Unicron. He's not dead, he's just possessing my cousin. He's going to try to plant his spark and take over Cybertron as a new body." The words were hardly out of his mouth when the blue and red Autobot leader appeared. Having heard everything, Optimus took something from his belt and handed it to Sam. The boy was surprised when he found the Matrix of Leadership now resting in his palms.

"What-"

"When Bumblebee informed me that you had disappeared into a room he had never seen, I feared that Unicron was not truly dead. It did not occur to me that he would take over a human body to transport his spark. If he succeeds in making Cybertron his new vessel, it will be the end of us all. Sam, you must stop Unicron. I believe the Matrix will help you."

"Why can't you stop Unicron?" Sam asked stubbornly.

"I must deal with Megatron. It is a lot to ask, I know, but you are the only one who can finish this." Sam nodded up at Optimus. It seemed that regardless of his own agenda, he was always destined to help the Transformers. "Be safe, Sam Witwicky."

Another explosion rocked the room as someone from outside the chamber attacked. Optimus turned and rejoined the battle, leaving Sam with Bumblebee and the controlled Mikaela.

"Keep her safe for me, Bee."

Anything for the boss. Bumblebee looked nervous. Sam smiled up at his guardian.

"I'll be fine. Even though Unicron's controlling her, it's still my cousin. And if anyone can stop her, it's going to be me."

A/N: I hope all that made sense. Let me know if any part of the explanation was unclear. I tried to cover anything, but I could have easily missed something.