When we got back to STAR Labs, we brought the tachyons with us which got us some confused looks from team Flash, that and the change of clothes. We told them what happened and what the tachyon particles were for, leaving out the part about how we figured it out.

"So if this is going to work, we need to get this to the center of the city, the focal point of where they spread out. From there, it should work as a sort of magnet, pulling them in. Either that or everyone dies," the Doctor summed up.

"Wait what?" I exclaimed. "Why is there a potential chance of the end of Central City?"

"Well, the probability of death is low but it could happen because it should be that the Klasoid transfer to different beings very quickly to get to the tachyons but too quickly for anyone to die. But there is the slight chance that I could be wrong and everyone could die. But that won't happen. If I'm right. And I most likely am."

I paused. "I trust you Doctor. And your judgment."

He smiled. "Good."

"Who are they?" We heard a gun being pulled out and we all turned to see Joe who had walked into the room.

I smiled. "Hi Joe! Don't worry, me and the Doctor are just here to help."

"Okay, I'll ask again. Barry, who are they?"

"Joe, they really are here to help. And um, Amanda knows who we all are because apparently on her earth all of this is a TV show and I'm the main character, right?" Barry explained.

"Yeah," I clarified.

"Her earth..?"

"Long story."

The Doctor then took his device and scanned Joe. "No Klasoid. But, I wouldn't go around touching people if I were you just for the time being."

"What are Klasoid?"

"Another long story. And we don't exactly have time to explain it all. Basically if you touch someone who has Klasoid in them, they transfer to you, they die. Then if someone touches you, you die. So, just don't touch anyone." I said.

"Okay, well how do I know I don't have them in me already?"

"Doctor just scanned you. You don't."

The Doctor clapped his hands together. "Now, where is the center of the city?"

...

"So what is this thing?" Joe asked, looking up at the massive machine that stood at the center of Central City.

"Well, I built is so that is can multiply the effect of the tachyons by about 50 so it should reel in the Klasoid stronger and faster once it's turned on," Cisco explained. "And it should be ready to turn on in three.. two.. one." He flipped the switch which powered up the machine. It pulsed a faint blue light. After about five minutes, he turned it off and the Doctor scanned it.

"This isn't right," he muttered.

"What is it?" I asked.

"Nothing happened. Didn't hear any screams so I don't think anyone died and there are no Klasoid on the machine."

"It didn't work," Caitlin stated.

"Oh come on! My tech wasn't good enough?" Cisco said.

"Maybe we forgot something. Doctor, you said the Klasoid could only travel through living things. Maybe because there's no living thing to travel to they didn't come?" Barry suggested.

"No that's not it. They only need to travel through living things. They can land on anything they want, they'll just be stuck there. They're attracted to tachyons. With the right amount of tachyons, they'll want to stay which means they don't need to travel anywhere after. So why didn't they come?"

"Man, I think you'll figure it out. I mean what you've done so far, it's great," Cisco said, slapping him on the shoulder. The two froze. "I didn't-" But he was cut of as his feature gradually went spotty until he was completely grey. A slight breeze came and all that was left was a pile of dust.

"Cisco!" Caitlin yelled, Barry whispered, and I half screamed. Dr. Wells stayed silent. We all ran over to what was left of him. I covered my mouth and my eyes widened in horror. Caitlin knelt down and let out a strangled sob.

"No, no no no! You weren't supposed to die! He wasn't supposed to die. If only the machine worked," the Doctor exclaimed.

Caitlin got up and faced the Doctor. "Bring him back. I'm begging you. Bring him back please!"

"I-I can't. I'm sorry." The Doctor said, a pure look of apology swept across his face.

She grabbed him by the collar of his shirt. "Bring. Him. Ba-" she was cut short as the Doctor turned grey and collapsed in a pile of dust. She stood there stunned for a moment.

"Doctor?" I looked over to see what had happened. My heart just about tore in two. "No. No. No, this isn't happening." I ran over to the pile of dust. "Regenerate. Come on regenerate. Regenerate! Come on. I don't care if you turn out looking super old, you're still the same Doctor! Come on, regenerate!" Tears started streaming down my face as I said this. "Regenerate. Please regenerate..." I stood up and turned around. There were tear streaks on half the faces that were there. I could understand why neither Barry or Joe were that sad about Cisco dying because they had only met him about a week or two ago. Eobard was going to kill him anyway even if he didn't know it yet. Me and Caitlin were closest to Cisco and I was the closest to the Doctor. I took a deep breath. "We should go back to STAR Labs," I said, my face stony.

"What about the machine?" Joe asked.

"I just lost my mentor and friend. I just need a moment to myself."

I got nods in return, and we left back to STAR Labs.