Optimus sighed as he transformed and drove away from the Citadel. Sadness and anger welled up inside him when he saw the first Guardian corpse. He was lying face-down in a pool of Energon, with nothing but his own severed limbs to keep him company. This would only be the first of the grisly scenes he would see as he continued down the road. Every Guardian and Elite Guardsman who wasn't engaging a Decepticon was already dead or dying on the side of the road.

As he continued to grieve for the bots that were already dead, his attention was drawn to Guardian Security Chief Ironhide, who was struggling to hold his own against a thuggish brute of a mech with a blue and orange paint job. He quickly transformed and fired on the imposing warrior, causing him to turn his head with a grunt. "Who're you?" he asked, opening the missile pods on his broad shoulders. "Think you can take me?"

"Whether I can or can't...take you...doesn't matter," Prime replied. "I cannot allow you to take the life of another friend. I've already seen enough Energon spilled tonight."

"Orion...That you, kid?" Ironhide asked weakly.

"In a way, yes," Optimus replied before punching the apparently dim-witted blue brawler in the chest, sending him flying backwards into a lamp-post. The brute responded by firing the powerful projectiles he carried in his shoulder launchers. Prime quickly drew his Ion Blaster and blasted the incoming missiles, taking them out mid-flight and leaving the one who fired them with a shocked and confused expression as he tried to process what had just happened. "Hey! No bot does that to Tankor!" the Decepticon thug growled before charging at Prime. "I'm gonna pound you into sheet metal, Guardian!"

Ironhide, whose automatic repair systems had been given some time to heal some of his wounds, pulled out his own blaster and fired on Tankor mid-charge, causing him to skid to a halt and look over at the red-hued Security Chief. Optimus seized upon the brute's distraction to fire some shots of his own, piercing through the somewhat weaker armor of the Decepticon's abdomen.

"Good thing this guy ain't too bright," Ironhide commented as he watched Tankor double over in pain.

"I'm afraid that, dull as his wits may be, he's far from the only Decepticon wreaking havoc on Cybertron right now," Prime replied. "There are others much more powerful and intelligent than he that threaten our way of life."

"Like that back-stabbin' piece o' scrap Metron?"

"Yes, although, apparently, he has re-christened himself as 'Megatron.' The prison break he orchestrated was a means of amassing an army and diverting the attention of the Elite Guard and Guardian Corps from him and his true objective."

Ironhide immediately knew who Prime was talking about. "Is Sentinel.."

"His Spark has been extinguished, but he will not be the last Prime. The Matrix has been passed on to another."

"It's you, isn't it?"

"Yes, Ironhide, it is. I am no longer Orion Pax. I am now Optimus Prime."

Ironhide saluted. "I'm ready an' willin' to serve, Prime."

"At ease, friend. For now, you should seek repairs. I'd rather not see another fellow Guardian lose his life tonight."

"That's gonna be easier said than done," Ironhide responded, shaking his head. "Every medi-bot on Cybertron seems to have his or her servos full 'cause o' the trouble these Decepti-creeps are causin'."

Optimus sighed. "I figured as much. The road to the Citadel is littered with fallen comrades, and I fear that this is just the beginning. I have already borne witness to Megatron's ruthlessness and cruelty. His hunger for power will not be sated by the death and destruction he has already caused."

Ironhide growled. "I always knew that bot was a no-good piece o' slag."

Optimus said nothing, instead just placing a consoling servo on Ironhide's shoulders, causing the grizzled red bot to smile, if only for a moment. Deep down, he could tell that Optimus Prime was still the same bot he had come to know as a friend in the Guardian Corps.

"What're your orders, sir?"

"Round up every Guardian and Elite Guard-bot we can spare. We can't let Megatron establish his tyranny over Cybertron."

"I'll do what I can," Ironhide responded before transforming into a vehicle similar to an SUV and rolling out. Prime soon followed him. Before they could get too far, however, they were stopped by a towering figure that Ironhide immediately recognized. "Is that...a Dark Sentinel?" the Security Chief asked in disbelief. To his knowledge, Dark Sentinels hadn't existed, or at least functions, since the Age of Subjugation, the period in which the Quintessons ruled Cybertron. Hovering above the behemoth was a purple and black Cybertronian gunship that was even more familiar to Ironhide than the Sentinel: Shockwave.