ALTERNATE DIMENSION (SENSEI-SENSEI)

Yuuko Ooshima the 9th could hear them. She could hear the voices of those girls, the understudies, who right now are fighting to take back Akibastar from the DES forces.
"Go on and join them."
Yuuko saw Maeda Atsuko the 13th encouraging her. Here in this alternate dimension, those that have been chosen to become Center Nova have been singing forevermore, to keep them from DES' grasp.
Yuuko nodded. "Alright. But.. one thing. I know before me, there has been a Yuuko Oshima who had become Center Nova… where is she? I don't see her here."
"Oh, her? Don't worry," Acchan replied. "She's fine. Her place is not here, but somewhere else…."

KOUSAKA RESIDENCE, EARTH, YEAR 2013

Honoka Kousaka, school idol and leader of the group Muse, was still in bed, despite the best efforts of her younger sister, Yukiho. "Wake up, Onee-chan! You're going to be late!"
"Wha-what? Let me sleep, Yukiho…"
Yukiho sighed. Fine, if that's the way it's gonna be.
She grabbed bucket of ice cold water and splashed it all on Honoka's face.
Honoka jolted upright. "What the hell, Yukiho!"
Yukiho shrugged. "Finally, you're up."
"Come on," Honoka said as she grabbed her alarm clock. "I'm not that late, it's only…"
The expression on her face changed as she realized that yes, she is late.
"Oh no, Umi-chan will be angry at me again!"
Honoka got up and rushed downstairs

OUTER SPACE, DES BATTLESHIP GUSION

"Captain, we have just received word. Akibastar has fallen. It is once again occupied by AKB0048."
Captain Hayato Nakajima slammed his fist on the armrest of the captain's chair in the ship's bridge. They were too late.
The Gusion was part of a small group that was sent to support the troops already on Akibastar.
"What about the commanding ship of the fleet assigned to Akibastar? What of the Barbatos?"
"The other members of the fleet were found in another sector of space. As for the Barbatos… whereabouts unknown, sir," the aide replied.
Nakajima shook his head. He was a seasoned commander, as can be seen from the lines of his face. He was already pushing fifty years old and is well-known throughout DES.
"Dammnit. Victory was already within our grasp, and you're telling me that not only we have lost a ship but Aikbastar has been taken back by those 00 fools?"
"Sir, we are detecting kirara nearby!" declared one of the men on the bridge.
Nakajima stood up. "Impossible. This area is currently under DES command, and there have been no reports of AKB operating in here. Where is it coming from?"
More typing from the soldier manning the computer. "Sir, it came from that wormhole."
Nakajima weighed his options. Maybe this was an AKB trick. But maybe…
He remembered attending this lecture once, about the possibilities in Space-Time. Maybe, just maybe…
"Enter the wormhole."
"… Sir?"
"Our fleet will enter the wormhole! Understood?"
"Yes sir!"
Nakajima sat down and closed his eyes, hoping that what's on the other side will be beneficial to DES.

"Sir!"
Nakajima opened his eyes. They made it?
"Alright, men. We made it. Zala, give me a status report!"
Zala gave no response.
"Hello? Zala! Status report!"
"Sir… look at that."
Directly in front of them was familiar planet. But instead of the wasteland that it was supposed to be, it was lush, with the oceans blue and the continents filled with green.
"Is that… Earth!?"
"..Yes, sir. According to our data, that is Planet Earth. And sir… you won't believe it, but according to our data, the year is 2013."
"So… we have travelled back in time?" Nakajima said. "And the Kirara response…"
Sir, it mostly likely came from there."
Nakajima thought about it. "Hmm. So it means there are idols already before, during this year. However, I'm pretty sure 00 doesn't exist yet, so if we attack them now that means we can stop 00 from forming!"
Nakajima smiled.
Finally, victory is ours.