Plagg went to look through the window of the small hotel room once more. Then went to the bed. And the window. Since they arrived, Felix has done nothing but looking at some papers, peering at his computer and writing. He was used to long periods inside pockets, lockers and such, but even a kwami patience has limits.

"Felix, you know you can go out and enjoy yourself while Chat Noir is not needed, right? You are in Paris, after all."

The British teen was licking close an envelope.

"First things first. Do you think I would jump into action without planning?"

The Kwami looked at the envelopes, and understood even less. Felix addressed them to Ladybug, 'the other Cat' and… himself?

"Well, now that plan C is taken care of…" he took some running shoes and shorts off his bag "I will see a couple of kilometers of the surroundings."

"What plan C" – The kwami couldn't finish his sentence, as Felix' computer started to beep.

"Well, there's an exercise better than jogging in town."

Plagg's eyes were glued on the screen, as the phrase "your alert for 'akuma' and 'Paris'" followed by video after video, news site after news site.

"Do you know how long I've waiting to say those words?" He raised his hand, wriggling the finger with his ring. "Plagg, transform me, servant."

"That 'servant' is uncalled fooooo.." but the kwami was already being attract to the ring, covering Felix's body in black material.

Twenty minutes after, Ladybug was swinging into the local where the Akumatized villain was causing destruction. This one was floating on what looked like an version of the TGV made of dark energy. The villain, a girl wearing a dystopian conductor uniform, had the power to send the train here and there, destroying building and streets. That was what Marinette saw on her mobile, while waiting the slowest ever pain d'épices to finish baking. She was not even sure what excuse she made to her parents. She must stop…

But the train was just floating there, while the villain was fending with a dark blur. Getting close, she remembered what Chat Noir said about the replacement. The guy was taller and lean, with longer hair. Where the uniform of her Chat was shiny, this one was dull black, with the boots going up to the middle of his thighs. The bell seemed oversized, unzipped to the middle of his chest. The mask was a bit more angular, reminding Ladybug of the ones wore in Venetian Carnivals.

And he was attacking the villain. Without stopping. Focused in the hero, she couldn't make the train move. That is, until the new Chat saw her. That gave the akumatized lady an opening to make a rail of energy appear and grow, throwing Felix away. Ladybug ran to him.

"Are you ok?"

"Fine." Said him, getting up. Both heroes looked at one another for a moment. "Introductions later?"

"Of course. Saw anything out of place on her?"

"Weak left defense. I just need a moment to knock her out."

"I mean out of place on her look. Something that should not be there."

Felix looked at the girl in steampunk-ish uniform, riding a flying train made of energy.

"Are you…kidding?"

After swinging close to the nemesis, Ladybug noticed.

"Her mobile."

"Right" said Felix "I will throw it for you."

With a swift movement of his stick, the phone was now flying in direction of Ladybug.

"Grab it! Grab and break it."

Marinette was about to say something, but decided not to antagonize the rookie.

"Now use your yoyo to catch the Akuma."

Soon, everything went to normal, with a young woman holding her phone in tears.

"He said his new girlfriend would arrive by train today. I still love him. I still…"

Leaving her to the authorities to handle, Ladybug turned to the new Chat.

"You did well, but I really don't need a backseat driver."

"You're also good. Shall we go on?"

"Uh… we're done here."

"No, we… he noticed his ring starting to beep, with one of cat's eyes becoming dark. "Meet me at the top of that building tonight, twenty-hundred. We need to talk."

Later that night, Ladybug swan to the meeting place, half-decided to give this new Cat a piece of her mind. At the distance, she saw him, emptying a backpack full of papers.

"Right, we started on the wrong foot. We'll work together for a while, so better know each one style, before…"

"Sure," he unwrapped a map of Paris "while we discuss my plan to capture Hawkmoth."

"What?"

"Look here. Do you think people don't get mad in Noisy-le-Grand? No personal crisis in Argenteuil? No arguing in Massy?" He pointed to the communes in metropolitan Paris. "Why are the attacks confined at this small area?" He smiled at himself. "Answer, Hawkmoth's powers are very limited geographically. Maybe, maybe even at the distance of sight. So now, we…"

"Wait. Wait. This is going too fast. First, I am not sure going hunting for Hawkmoth is the best action. Second… No, first of all, I don't think I can call you Chat Noir."

"Felix is fine." He paused for a while "Or Dark Cat. Yes, Dark Cat can work." He packed up "Come with me" and used his stick to propel him.

Ladybug sighed and followed. These are going to be some long weeks.

After a while, Felix landed on a known building.

"And here we are."

"The College Françoise Dupont?" but he was already propelling himself to the inner courtyard.

"Dark Cat, you are trespassing." He didn't seem to listen.

"There are a few Akuma magnet's places on my list. This one takes the cake. Horrificator, Evillustrator, the stone guy. Coincidence? I don't think so." And raised his stick to break a window. Ladybug hand stopped him.

"I said you can't do this."

"Look, Ladybug, this can be home of an insane principal, a delusional teacher, a janitor with a complex. And next time, he can do damage that you can't undo. So let's end this at once."

"We…" she measured her words "Me and Chat Noir will stop Hawkmoth. By the book. Not breaking in every place you thinks is suspicious."

"Have it your way." He raised his hands in a shrug motion, but suddenly firmed the grip around the baton and made it grow, smashing the window. He smiled. "Oopsie."

He was about to enter, when he felt the line of Ladybug's yoyo around him.

"I said no."

He stopped for a while. "Very well, in the name of partnership, I shall oblige."

"Look, let's just try to work together for a few weeks, right? Doing it the usual way is already dangerous enough."

"Very well, I will play the sidekick. As for the few weeks… who knows?" And jumped out of Ladybug's view.

Back in her room, an exhausted Marinette collapsed in the bed.

"Tikki, can you believe this guy? A couple of minutes with him and I am already missing the cat puns."

"Some people have difficult personalities, Marinette, but we must make an effort to…"

"Difficult personalities?"

"It's a way to say he is a jerk with an ego the size of the Stade de France."

"Tikki!"

"But go easy with him, and you may work together in a more friendly way."

"I hope so. At least, he will not do anything stupid."

The next night, Dark Cat was exploring the college alone.