STAR Labs
Cortex
"No sign of tachyon activity," Cisco said.
"We're running out of time. We've got to find them," Barry said.
"We will, Barry," Kara assured.
"It'll take a few minutes for the device to reach full power once it's activated, but when we find it, you're gonna have to get there fast," Cisco said, but then Joe & Mon walked in, and walked up to Barry & Kara.
"Hey. We have a problem. Like, identity reveal bad," Mon whispered to them.
"What?" Kara asked, but then he and Joe pulled Kara & Barry out from the cortex.
"Patty knows you're The Flash & Supergirl," Joe dropped the bomb, and the two looked at the two in utter anger.
"What?!" Kara exclaimed quietly.
"She caught us off guard!" Mon exclaimed.
"I mean, we played it off, but come on, she's a smart girl. Anyway, she was going through some case files and you were acting all squirrely," Joe said.
"This is my fault now?" Barry asked.
"No, it's nobody's fault," Joe said.
"Maybe you should tell her," Mon said.
"No!" both Barry & Kara snapped.
"Patty's trustworthy," Joe said.
"It's not even about that, Joe. I-I don't want another person that Zoom or Reverse-Flash or any of these meta-humans or any other alien notjub can use against me or Kara," Barry said. "I don't want it. Patty can't get hurt over this."
Then the whole place boomed in an alarm. "Tachyons!" The group ran back into the cortex to find Cisco at a computer. "87th and Avenue J. Must be one of Mercury Labs' off-site facilities," Cisco said, then Barry zoomed off.
"Hack into their se-" Harry started to say.
"I've hacked in the security feed," Cisco said.
"And once that-" Harry started to say.
"I'm one step ahead of you," Cisco said, then they all saw Thawne in the Reverse-Flash suit walk up to Christina in the footage.
"Barry, hurry up!" Kara said to Barry through the mic.
87th and Avenue J.
Thawne walked over to Christina, in his reverse-flash suit. "It's charged. You can go now. You said you'd release me," Christina said.
"Yes, I did. Didn't I?" Thawne said before he started vibrate his hand above her head. But then Thawne Flash zoomed in and pushed Thawne out of the way.
"You okay?" Barry asked Christina and she nodded. "Okay, get out of here, all right? Go! Go!"
Then she ran off, as Barry zoomed over to the tachyons and destroyed the machine. "That was my way home!" Thawne yelled, and Barry faced him.
"You're not going anywhere," Barry said.
"You haven't won here, Flash. I'll find another way back," Thawne said.
"You're gonna have to get through me first," Barry said.
"You really think you're fast enough to stop me?" Thawne asked.
"Let's find out. Catch me if you can," Barry said before he zoomed off.
Warehouse
The Flash and the Reverse-Flash zoomed into the warehouse, with Flash pinning Reverse against a gated wall. "Not fast enough, Thawne," Barry said, before he started to beat on Thawne. "I will never lose to you again," he continued as he kept beating on Thawne. "This war between us, it ends now!"
"Bar, you got to stop!" Kara's voice lit up through Barry's ears in the comms. "Bar, don't kill him! Just bring him in!"
Barry suddenly stopped but then he knocked Thawne out with one more punch. "Get the cell ready," Barry said.
STAR Labs
Cortex
The group watched Thawne in his cell, from footage. "Hey, he can't...?" Barry started to ask.
"Phase his way out? No, he can't do that," Cisco said.
"It's the same cell we used to hold Dr. Wells last year," Caitlin said, but then Barry started to walk out of the cortex.
"Barry, where you going?" Kara asked.
"I'm going down there," Barry said.
"No, you're not," Kara said.
"The more he learns about you, the more you will alter the time line," Harry said.
"He killed my mom!" Barry yelled.
"He's from the future. He hasn't done that yet. He doesn't even know you're The Flash, and that Kara is Supergirl and you need to keep it that way," Harry said.
"You already said that his mother's gonna die no matter what we do," Joe said.
"There's ramifications any time anybody messes with the time line, and it's impossible to predict what those ramifications are going to be," Harry said.
"Barry, you caught him and you stopped him from killing Dr. McGee. That's a win," Kara said.
"This doesn't feel like a win," Barry said, but then his cell phone vibrated. "I got to go," he said before he left the cortex.
STAR Labs
Pipeline
The door opened and Thawne looked out of his clear cell gate to see Cisco on the other side. "How'd you get your suit in your ring?" Cisco asked.
"Who are you?" Thawne asked.
"My name is Cisco Ramon," Cisco said.
"And we know each other well, don't we? We have a history together," Thawne said.
"You could say that," Cisco said.
"And that's all you want to know? How I got my suit in my ring?" Thawne asked.
"I want you to know that I'm the one who figured out you were back. I helped stop you. Me," Cisco said.
"And how'd you do that?" Thawne asked.
"I have powers. And I helped track you down and I put you in here," Cisco said.
"That's quite the ability you've been given," Thawne said.
"And here's what's so ironic about it. You gave me these powers. Have fun thinking about that while you rot away ithis cell that you helped me build. Bye, Felicia," Cisco said before he smiled and closed the door.
CCPD: Barry's Lab
Barry walked in to find Patty was already in there. "Hey. Got your text," Barry said.
"I wasn't sure that you would see me, considering you've been avoiding me lately," Patty said.
"Patty, I haven't been avoiding you," Barry said as he walked near the window.
"No, just, uh, busy...you know, speeding around Central City," Patty said and Barry faced her. "With Kara." Barry stared at her hesitantly. "I know you're The Flash and Kara is Supergirl, Barry. This explains why you and her are so close, even though you're broken up."
"Patty, come on," Barry said.
"Please don't make me feel any more stupid than I already do. Look, I'm a detective and I should have known. I was just...I was so smitten with you," Patty said.
"Okay, look, what...What you're saying, it's insane," Barry said.
"Look, you don't have to lie to me anymore, okay? I understand...I understand why you didn't want to tell me. I understand why you've been distant. Look, I understand everything. But just tell me the truth now. Just be honest with me. Just...admit to me you're The Flash and I'll stay," Patty said.
"I can't do that. I'm not Him. And Kara is not Her," Barry said.
"It's too bad. It would have been nice to stay," Patty said as her voice started to crack. "Fight crime during the day and be with you at night." She then started to cry. "But I was...I was wrong. Take care, Barry," she then walked away from Barry and out of the lab.
STAR Labs
Pipeline
The door opened and Thawne looked out of his clear cell gate to see the figure of someone, who was standing in the shadows on the other side. "Is that you, Flash?" Thawne asked.
"Why do you hate me so much?" Barry asked in the shadows.
"I didn't always. I was obsessed with you. For so long, I wanted to be The Flash. Because you got everything. The fame, the glory, you even got yourself Supergirl. I spent years figuring out how you came to be. Duplicated the reaction...and it worked. I became like you," Thawne explained.
"Right, so what happened?" Barry asked.
"This ability to travel through time revealed a truth. My fate was to become your greatest enemy. I was never going to be The Flash, so I became the reverse of everything that you were. The more people you saved, the more you were loved, the more I had to take from you," Thawne said.
"That is why you killed my mother? That's why you ruined my life? Because you couldn't be me?" Barry asked.
"I became better than you! I am the one thing you cannot stop, Flash!" Thawne yelled.
"No, no, no. Not anymore. Our race is over. And you lost," Barry said.
"I've learned what time period you're from, Flash. And one day soon, I'll learn your name. And when I do, I'll kill everyone you love, including your Supergirl. Then I'll kill you," Thawne said as Barry tightened up his fist at Thawne's threat of hurting Kara.
"We need you in the med bay now!"
STAR Labs
Med Bay
Barry ran into the med bay, to find everyone surrounding Cisco, who was having a seizure. "What's happening?" Barry asked.
"He's experiencing an uncontrollable amount of electrical energy in his brain, putting him in a prolonged state of chronic seizing," Caitlin said.
"What? Can you stop it?" Barry asked.
"I don't know. Hold him down!" Caitlin exclaimed and Kara & Mon began to pin him down.
"Sedate him, Snow, now!" Harry ordered then Caitlin grabbed something.
"Benzodiazepine. This should do it," Caitlin said before she injected it into Cisco and he stopped seizing.
"Finally," Mon said as he and Kara let him. But then Cisco started to disappear.
"Oh! What? What was that? What's going on? Where the hell am I?" Cisco asked.
"Cisco!" Kara exclaimed.
"It's the time line," Harry said and everyone looked at him.
"What? What are you talking about?" Barry asked.
"When you...when you captured Reverse-Flash, we ruptured the time line. That's what this...All the blood and the seizures and that and all...Cisco is being affected to...to...By the changes to the time line. The changes to the past or the changes to the present...This is what this is. We need to do something. We need to do it fast," Harry said.
"Like what?" Barry asked but then Kara faced Barry, knowing what they had to do.
"We need to restore the time line," Harry said.
"Barry, you need to get Reverse-Flash and send him back to the future," Kara said and he looked at her like she was crazy.
"What? Are you-" Barry started to say.
"Barry," Kara said calmly.
"I just caught him! You want me to let him go?" Barry yelled.
"Keeping him here is killing Cisco! Barry, if this is the only way we can save him, you got to do it!" Kara yelled back and Barry put his hands behind his neck.
"Okay, all right, look. I destroyed the tachyon drive in the speed machine. There's no way it'll reach a speed necessary to send him back home," Barry said.
"You can," Mon said.
"What?" Barry asked.
"Your speed coupled with Thawne's speed, that'll be enough to catapult him through the time continuum," Mon said, then Kara made Barry face her by taking his hands.
"You can do it. I believe in you," Kara said and he nodded.
STAR Labs
Pipeline
Harry walked in and opened the door so that he could talk to Thawne. "Time to send you home," Harry said.
"The time paradox. You've all messed with something you don't understand," Thawne said.
"Can you do me a favor and just shut up?" Harry asked and Thawne laughed.
"And how exactly are you going to send me home?" Thawne asked.
"Don't worry about it," Harry said.
"You fixed Dr. McGee's tachyon device?" Thawne asked.
"No, I came up with a different method," Harry said.
"Is that so?" Thawne asked.
"Uh-huh," Harry said.
"Who are you?" Thawne asked.
"No one of consequence," Harry said.
"No. I doubt that," Thawne said.
----
Harry, Kara & The Flash all stood before the Reverse-Flash, who was smirking at all of them. "I win again, Flash," Thawne said and Kara grabbed Barry's hand.
"Don't talk to him," Kara said to Thawne before she and the others faced Barry.
"All you have to do is provide him with enough momentum to get him past the space-time barrier," Harry said and Barry nodded.
"All right," he said.
"Hey, listen to me. Thawne knows about you. Right here, right now. This is where he learns about you, all of you. It's how he knows about S.T.A.R. Labs, how he knows about me...The Harrison Wells from this Earth," Harry said.
"And there's nothing I can do about it," Barry said.
"There's nothing you can do about it. This is his origin story, and it's going to happen no matter what you do. But right here, right now...you can send him back to his time. You can save your friend. You can save Cisco and then move on with your life. This could be a good thing. You can finally let go of him," Harry said.
"I could throw him three centuries from now. He'll always be a part of me," Barry said before he faced Kara.
"I'll be here, waiting," Kara said before she lifted up on her tiptoes and hugged him. He hugged her back, feeling her warmth, savoring the moment, then they parted. He then faced Thawne as Kara & Harry stood by.
"Time to send you back where you belong," Barry said.
"We'll meet again soon, Flash," Thawne said.
"I know. And every time, I'll be ready for you," Barry said, but then Thawne slowly glanced over at Kara, who was glaring at him.
"Don't look at her," Barry said and Thawne looked at him again. He then zoomed into the particle accelerator and Barry watched him go before he looked back at Kara.
"Hurry," she whispered to him and he nodded before he zoomed off into the particle accelerator. Kara then looked at Harry with a stern look. "Go," she said and Harry ran out of the pipeline.