"Hi. Living in a house so small and full of people you may think it's impossible to have privacy and secrets." The lean boy with white hair stopped walking the hallway of his house and lowered his voice "but we still manage."

"Linc…Numbuh 52, meeting tomorrow at 1600." A young girl with oversized glasses quickly gave him a paper.

"Thank you, Lisa."

She gave him a stern look and adjusted her glasses.

"I mean, 'L'."

"Better. Now, if you excuse me…"

She quickly went down to the basement. Making sure she was alone, she opened a hidden panel, entered a code. The water heater opened, revealing a long sliding tube she went down in, travelling through impossible lengths and angles, surfacing on a bookstore.

She found her target. In fact, that was the easiest part of the mission. A bald, sunglass-wearing kid, looking extremely bored watching a puppet show surrounded by much younger children. She sat beside him.

"So, what are the puppets doing?"

He looked at the newcomer and sighed. That was just what he needed, practically a baby to make difficult for him to meet the new technology expert. He has to find a new place to stay, quickly.

"Some gag to amuse toddlers like you. I am leaving."

"Funny. I see a bald puppet who is wacked in the head too many times for his own good. Sit down, Numbuh One."

For a moment, he forgot about the safety, raised his glasses and looked straight at her.

"L? Are you the new L? They must be kidding."

"Younger age discrimination is an irony considering our organization."

"I was expecting someone old enough to at least tie her own shoes."

"I could give you a lesson on the history of shoes, as well as the socio-economic effects of the present manufacture of sneakers on poor Asian countries. But it would not help our case. Here." She passed him a small box. He opened it, revealing a birthday invitation, a pack of gum and a keychain with some Japanese hero figure in it. She started to explain.

"The gum can expand creating a web capable of engulfing up to two enemies. DNA-coded to your saliva, so no one else can use it."

"What about this?" He raised the keychain; she quickly flipped the character head, revealing a red button.

"An advancement from our labs. It's called a radio."

"What else?"

"That's it"

"Gum and a radio. It's not exactly Christmas, is it?"

"What were you expecting? A naked missile or a submergible ball court? We no longer do those things, Numbuh One. Consider yourself lucky we still need someone to chew the gum."

With that, Lisa Loud quickly leaved, leaving the field operative to his own thoughts. Before entering the tube to return home, she took a paper from her pocket and sighed. A birthday invitation, the same she just gave to Numbuh One. The birthday party of her own sister.

The one she just betrayed.

OPERATION: L.O.U.D.: Latest Operative Unlikely Decomission

A Kids Next Door/Loud House crossover

The author does not own nor claim any right or connection with Operation: Kids Next Door, Loud House, its characters and settings, Nickleodeon Animation Studios or Curious Pictures.

Story for entertainment purposes only

Reviews, opinions and "aw, c'mon!" appreciated.

A candy to whoever discover why Lincoln's number is 52, and Lucy's 49. Tip: read it "five-two" and "forty nine"

Please enjoy.

The house of the Louds is bursting with activity. Balloons are being inflated, streamers and festive decorations go up here and there, the smell of a cake on the oven fill up the air. The Loud kids are excited as they can be. Well, most of them. Lincoln Loud tried to meddle with his sisters but gave up and run upstairs to his room.

"You know" started Lincoln "Birthdays are a very common place here in our house. We usually welcome a whole day when each of us is the center of attention, but this one…this particular birthday I wished would never come."

"Numbuh five-two."

"Aaaaagh!" Lincoln jumped with fear, He was sure he was alone, but his sister Lucy, wearing all black clothes like always, appeared from nowhere.

"Lucy, don't d…"

"SIGH!"

"Right, official business, Numbuh 49, don't do that again!"

"I can't find L."

"She must be at Headquarters. They're always in need of her brain there."

"Perhaps. But our parents will grow suspicious if she's not here soon to help with the festivities. I also can't find Numb… SIGH! … can't find Luan. But that is expect."

"Yes" Lincoln lowered his head. "I have problems with the codenames, but it's hard to believe there will be no longer…"

"Numbuh Custard 3.1416." Numbuh One showed a photo of a girl with ponytail, braces and a red clown nose to Numbuh Five, who was riding in the back of a car with him. "Real name, Luan. Former leader of Sector Double L."

"The siblings sector."

He passed more photos to her. "Yes. Numbuh five-two, Numbuh 49, and the new L." Nigel Uno grinded his teeth, remembering the encounter with the smart toddler. "Be careful. There are many other kids in the house. Some do not had the desire of joining Kids Next Door, others failed the exams. We may encounter some grudge against us."

The girl chuckled and answered in the third person, as she sometimes does

"Numbuh 5 still thinks it's a simple escort mission. Not every operative runs from their decommission."

"And not everyone goes peacefully. Everyone turns 13, but not everyone is ready for it."

"Numbuh 5 can't imagine why. All we do is practically kidnap them, erase their memories against the will of most and kick them out of organization." She crossed her arms and looked through the car window "This can be my last mission, Nigel. I have less than two months. Another three months, and it's you who will become a teenager. Not only we'll forget about everything we went through together, I am not sure I will be even capable of recognize you."

Numbuh One remained speechless. He forgot – or tried to forget – the increasing fear Numbuh 5 has of her 13th birthday. Bringing her together for such a mission was a mistake. She looked at her friend, as reading his mind, and opened a quick smile.

"Don't worry. Numbuh Five's a professional. You and me, we'll get the birthday girl with no fuss or second thoughts. We're here."

"Have fun, kids" Waved Numbuh Five's father, driving away. "Don't eat too many candies, and hot-dogs, and cake, you know what I am talking about."

Nigel Uno took the chewing gum and keychain from his pocket. This mission better be an easy one. He looked at the Loud's house,in front of him.

"Now" he said "Where's Numbuh Custard 3.1416?"