Miraculous and The Flash crossover: Collision of Worlds. (Book 4)

At the Champ de Mars, Kagami was finishing up her fencing practice for the day, and was heading back to the car.
However, she couldn't shake the feeling that she was being watched.

She turns around and inspects the area behind her.
After a few seconds of seeing nothing, she walks away.
Unaware that Argos was watching her, from the trees, thinking to himself.

*Argos: “Don’t worry, Kagami. When I merge the Miraculous of Ladybug and Cat Noir. I'll create a free world for the both of us.”

He then sees a rush of lightning rushing past.

(WHOOSH!)

*Argos: “Oh, right. Flash. He might be a problem.”

He follows after him, leaping across the trees, the Eiffel Tower, and multiple rooftops.

*Argos: “But what could he possibly be up to?”

He watches as the rush stops outside of a building.
Revealing Barry Allen, standing outside, and heading inside.
Leaving Argos staunchly confused.

*Argos: “I don’t believe it! The Flash is, is…I actually have no idea. Who is this guy?”

Now, in his apartment. Barry checks his computer, and goes over all the connections between Tsurugi Industries, and Gabriel's brand. Gideon activates and appears while he investigates.

Gideon: “GOOD EVENING, BARRY ALLEN.”

Barry: Gideon, how are we doing with the final rendition to the Tachyon Enhancer and Still Force particles?

Gideon: “THE RENDERING TO THE TACHYON ENHANCER IS ALMOST DONE. WE JUST NEED ONE LAST COMPONENT TO COMPLETE THE TACHYON ENHANCER, AND RETURN TO EARTH 1.”

Barry: I know. We still need to find a tech component capable of reacting with my Speed Force energy and restoring my normal age. But where can I find it?

Barry suddenly gets an idea, and searches through Tsurugi Industries archives, using a flash drive Barry swiped while he was in the archives. He then gets an email from Sabrina.

@sabrina_raincomprix: “Okay, here's everything that I could find about Tsurugi Industries' connection to Gabriel's fashion brand.”

He types on the keyboard in response to Sabrina.

@barryallen: “Thanks, Sabrina. And in return, I'll be sure to do your homework for the rest of the week.”

Barry waits a bit, and another email pops up.

@sabrina_raincomprix: “You don't have to do that for me. But, I appreciate your offer. Thanks.”

@barryallen: “No worries.”

He closes his email and goes back to searching through Tomoe Tsurugi’s files for the component he needs. When he heard a knock at the door.

(Knock! Knock! Knock!)

Barry gets up and checks the peephole. He sees Lila standing outside his door. He opens the door and lets her in.

Barry: This isn't a good time, Lila. I'm a little busy.

Lila: I know, Barry. But I wouldn't have come, unless it was something serious.

Barry sits down at his desk, again.

Barry: Okay, Lila. What's going on?

Lila: Well, it feels like I've been hearing…voices.

Barry: Voices?

Lila: Yeah, I keep hearing them telling me that you're not really my friend, and how you're just using me.

Barry: Lila, you know I've given you little to no reason to not trust me, right?

Lila: I know, and I appreciate that. But…I still don't know you that well. You're either working on a case, or out fighting supervillains.
Which, I know is your whole deal, but–

Meanwhile, Barry notices something near his window.

Lila: Are you even listening, Barr–?!

Barry quickly covers her mouth, and puts a finger to his own.

Barry: (Quietly) Shh.

He points to the window and Lila turns to the window.
Sitting just outside it, was a strange pair of eyes.
Barry gestures to stay quiet, and proceeds to vibrate beyond the visible spectrum. The eyes appear again. But this time, it's whole body appears. The strange creature takes the form of what looks like an Akuma. It flies around Barry's apartment, but Barry, now in his Flash uniform, catches it in a jar.

Flash: Ha! Gotcha!

The strange insect flaps around the jar, trying to escape.
Lila stands next to Flash, in order to get a closer look.

Lila: What kind of Akuma is that?

Flash: It's not an Akuma. Doesn't even look like a normal butterfly.

But before Barry could say anything else, Argos snaps his fingers, and the strange butterfly disappears, in a dark blue void. Leaving the two of them shocked.

Lila: What the heck?!

Flash: It was a Senti-monster! Someone was spying on us using the Peacock Miraculous!

Lila: But who would–?

Flash looks outside his window to see a figure leaping across the rooftops.

Flash: I'm going after him!

Lila: Wait! What am I supposed to do?

Flash: Use my comms center, Gideon can help you out. Gideon?

Gideon activates the comms on Flash's computer. And a satellite display of Paris appears on the screen.

(WHOOSH!)

Flash rushes out.

Lila: Right, okay. No big deal.

Lila sits down at the computer, monitoring Flash, as he chases after the unknown spy.