What happens when you summon Emiya Shirou in Chaldea

I Am A Gundam

"Eh? You want me to test out another new mystic code?" Shirou asked Da Vinci as they were in the testing room of Chaldea.

"Yes. And this time, there's nothing wrong with it." Da Vinci replied.

"Are you sure?" Shirou asked with suspicion in his voice.

"Yes! Unlike the prototype mystic code from earlier, this mystic code doesn't have any problems with the construction! I even double checked it!"

"And why do I need to do it?"

Da Vinci had a smug look on her face. "Call it...payback from earlier."

Shirou didn't know what she meant until he realized he has an unpaid debt to Da Vinci from a while ago. He let out a sigh and said, "Well...if you say so..."

"Yes! Now if you'll let me get the mystic code for a moment..." Da Vinci said as she went to a corner of the training room and brought out the mystic code she was talking about. As she returned to where Shirou was, she presented the mystic code to him.

The mystic code itself was a sword, something that Shirou was familiar with. The sword itself was a one-handed sword in which the blade itself was in a transparent green color with some white on the middle of the blade in a design-like shape. The sword's cross guard along with the grip was in a dark grey and it had what it seems to be exhaust ports on the sides. It has a blue-colored knuckle guard.

All and all, it looked like it was made in the future.

"Is this it?" Shirou asked as he was examining the mystic code/sword.

"Yes. Why? You don't like it?" Da Vinci asked.

"It's not that. It's just that...well...the design looks quite similar to something, but I can't remember what it was..." Shirou replied.

"I see. Anyways, try swinging it around a bit."

Shirou complied to Da Vinci's request and started swinging the sword around. As he swung the sword, he thought, "This sword...the more times I keep swinging it and looking at it, the more familiar it gets. But where have I seen this weapon before?"

"Shirou? Are you okay?" Da Vinci said, snapping Shirou out of his thoughts.

"Hm? Oh yeah. Sorry Da Vinci, I was in my thoughts for a moment." Shirou replied.

"I see. Anyways, what are your thoughts and feedback on the mystic code/sword?"

"It's a good mystic code/sword, although I can't help but feel like I've seen this before. The problem is, where though."

"Maybe it's just your imagination."

"You think so?"

"Yeah. Anyways, there's more to this mystic code/sword than this."

"What do you mean by that?"

"Well...do you see a certain grey button on one of the sides of the cross guard?"

Shirou looked at a sword more closely and saw a small switch on one of the sides of the cross guard. "I see it. So what?"

"Well...press it and see..." Da Vinci said with a mischievous grin so creepy it was actually scaring Shirou a bit.

"O-Okay..." Shirou muttered, not wanting to question even further after seeing that smile of hers. As Shirou pressed it, nothing happened.

"Phew. Guess nothing happened then..." Shirou thought as he sighed in relief. Then he was encased in a bright green light. "On second thought, never mind," he thought as sighed again.