Y/N and Barry walked into the Arrow Cave to see Oliver discussing something with his team, Felicity by his side. Barry and Y/N quietly waited off to the side until he was finished.

"Hey," Felicity said coming down to greet Y/N and Barry, Oliver just behind her.

"How are you?" Y/N said giving Felicity a hug.

"Good, a little nervous, but good."

"Oliver, what about you?" Y/N asked.

"Never better," he said putting his arm around Felicity.

"Do you guys need something?" Felicity asked.

"No," Barry said shaking his head. "For once, everything seems somewhat okay in our lives."

"Well, we do have this unknown guy hunting us, but that can wait until after the wedding," Y/N said as if it was nothing.

Barry chuckled putting his arm around her and pulling her close.

The next day was seemingly perfect. The ceremony had begun, everyone was there, Team Flash, Team Arrow, Supergirl and her sister Alex, as well as The Legends...and that's when all hell broke loose.

Just as the pastor said the "Speak now or forever hold your peace," a group of what appeared to be Nazi soldiers stormed into the church.

"Peace if overrated," one of them said, they all wore masks that covered their faces.

"You have got to be kidding me," Oliver said in disbelief.

"Nazis?" Felicity asked.

"I hate Nazis," Barry and Y/N said in unison.

That's when they opened fire on everyone. Barry and Y/N focused on getting everyone out to safety, meanwhile Oliver and Cisco breached and grabbed weapons for everyone. Once everyone was brought to safety Y/N and Barry joined the fight. Y/N noticed a speedster dressed in yellow, but it wasn't long until they retreated and the heroes were left there...stunned.

"Who the hell were they?" Kara, A.K.A. Supergirl asked.

"Something tells me that they are our next problem," Sara, A.K.A White Canary, replied.

Everyone headed back to the Arrow Cave to recover, and process what had just happened.

Barry sat in a chair while Y/N ran a hand over his cheek while she looked at a gash on his cheek that had happened earlier.

"I'm fine, really," he said putting his hand on hers.

Y/N nodded, "I'm just glad you're okay."

"I'm glad we're both okay," he said, his forehead leaning against hers.

"Our lives are crazy," she added.

"Hey," Barry said cupping her face in his hands, "We're gonna be okay..."

Y/N nodded and the couple stood up together and headed over to the rest of the team.

"So why would Nazis from 1945 want to crash a wedding?" Kara asked.

"No," Y/N said shaking her head. "They had a speedster on their side."

"So if they're not from 1945, then where are they from?" Sara questioned.

"What if they're visitors from another Earth?" Barry suggested.

"Another Earth? How many are there?" Oliver asked.

"Infinite, but something makes me think that they might be from Earth X. It's exactly like this Earth, except for one critical difference," Y/N added.

"What difference?" Alex, Kara's sister asked.

"The Nazis won WWII."

"Okay, but why would they want to attack us?" Barry asked.

"A room full of superheroes, eliminate Earth's line of defense. Seems like a pretty good idea if you ask me," Oliver said.

"So what do we do next?"

"We prepare, and we fight....this is our Earth," Barry said as everyone scattered and began getting ready.

Y/N began walking away when Barry grabbed her hand and pulled her back towards him.

"Is something wrong?" she asked looking a little worried as Barry turned serious.

"You said that they had a speedster."

"Yeah, dressed in yellow, similar to Thawne, but still a little different somehow," Y/N said describing what she saw.

"I think I might have an idea as to who he is," Barry said leading her towards the door. They both sped back to Central City, and then to S.T.A.R. Labs, more specifically, the time vault.

"What are we doing in here?" Y/N asked while Barry led her towards the console that housed a version of Gideon in it.

As Barry turned it on it revealed information of a man named Eobard Thawne, in Harrison Well's body. 

"Is that him?" Barry asked.

Y/N nodded walking closer and observing what Barry had put in front of her. She turned back towards Barry only to see him looking at the ground, and worrisome expression took over his face.

"That's Eobard Thawne, with the face of Harrison Wells. The same face he wore when he ruined my life...when he betrayed me."

"Barry.." Y/N whispered walking closer.

Barry closed the distance quickly and wrapped her in his arms, his face buried in her neck.

"He stole everything from me, and every time I look at him...all I see is my mother being murdered over and over again," Barry murmured into Y/N's hair.

"Barry," Y/N said pulling away to see Barry's face, "We're gonna get through this...together."

Everyone had returned to the Arrow base once they heard of an attack on a Medical Company in Star City. Oliver, Kara, Barry, and Y/N had all suited up.

Barry and Y/N arrived first, then Kara, and they looked around, but didn't see Oliver.

And then they saw him come over a hill on his motorcycle, as he got off, "Just a quick remimder...super speed...I don't have it."

"Noted," Barry said as the trio walked towards the building, as they did so they saw three individuals walk out.

"A little late," one of them said setting down whatever they had stolen.

"You might as well just surrender now, otherwise we're just gonna end up kicking your asses," Y/N said with confidence.

One of them chuckled, "Yes, you are good, but we're better. You've fought villains, metahumans, aliens, and the list goes on. You've fought the worst of the worst....but let's see how well you can fight us," they all said in unison as they removed their masks.

They were the doppelgangers of Oliver and Kara....and Eobard Thawne was working with them.