A/N: First full chapter! Enjoy!

Chapter 1: We Want In

Mabel and Mason Pines weren't that well known in their year. They didn't blend into the background like Sally-Anne Perks or Roger Malone. But they weren't the most well known like Harry Potter or Draco Malfoy.

But it wasn't that they were just there, they both had their quirks. Mabel was well known for her homemade sweaters (well school made sweaters) and everyday during class she had a different one that was Hufflepuff themed and during weekends she had just random things. She was also well known for being bright and cheerful.

Her brother was known for wearing a particular hat outside of class, a brown baseball cap with a star on it. Also his quill chewing habit whenever he was in deep thought, he was into mysteries and often came up ideas. Also he insisted on his nickname Dipper, though no one knew why or what it meant.

Plus there was the fact they were born in America but moved when they were younger and still had their American accents and they were both Muggleborns.

Although they were in different houses, they hung out during any free times they had or paired up during the classes they shared.

However this year a huge mystery was going on, The Chamber of Secrets.

On Halloween, the message appeared saying "THE CHAMBER OF SECRETS HAS BEEN OPENED! ENEMIES OF THE HEIR BEWARE!" with Filch's petrified cat nearby.

They had found out that the Chamber of Secrets was something Salazar Slytherin built that housed a horrible monster.

Dipper wanted to figure out everything that was going on, not only who the heir was but also what the monster was. And he wanted figure out the latter first.

And Mabel was right by his side as he figured it out.

"Okay…" said Dipper starting to chew on the quill, "Since Slytherin symbol is a snake it must be…"

However he began to choke on the quill. Mabel began to pat his.

"Dipper you have to use a sugar quill, remember." Said Mabel patting his back.

"I know." Said Dipper.

"Have you figured anything out yet?" asked Mabel.

"So far it has to be some sort of snake creature." Said Dipper, "Since he was one o the most powerful wizards of his time, he would have figure out how to keep alive if it wasn't long lived already."

"Maybe it's some sort of giant man-eating snake!" laughed Mabel.

"You might not be too far off." Said Dipper.

"Excuse me." Said a voice.

They looked up and saw Hermoine Granger, one of the top students in their year and was in Gryffindor.

"We you talking about the monster?" she asked.

"The one in the chamber of Secrets." Said Dipper.

"He figured out that it's some sort of snake!" said Mabel.

Hermoine was surprised, "I didn't think of it." She said.

"I figured it would be better to figure out what the monster is so we can figure out ways to stop it." Said Dipper.

Hermoine was surprised and impressed.

"You're trying to figure it out too?" asked Hermoine.

"Of course considering we're both "enemies of the heir"." Said Mabel.

Hermoine nodded realizing it meant they were muggleborns.

"Hermoine what are you doing?" they heard Harry Potter call out.

"Oh sorry." Said Hermoine, "It was nice talking to you."

She left and joined her friends in talking to the librarian about a certain book.

"She's trying to figure things out too." Said Dipper.

"Come on let's go follow them." Said Mabel.

"What?" asked Dipper.

"Remember what they did last year!" said Mabel.

"Well." Said Dipper.

"Come on they're planning something." said Mabel, "Besides we all know whatever they're planning is going to be interesting."

Mabel grabbed his hand and tailed them.

They saw they entered the bathroom.

"Did all three of them enter the girl's bathroom?" asked Dipper.

"It's Moaning Myrtle's backroom." Said Mabel, "No one uses it because of that."

"I see…" said Dipper.

They both headed to the door and found it wasn't easy to open.

"So how we get in." said Dipper.

"Oh Dipper…" said Mabel, "I already thought of an idea."

"Really what?" asked Dipper.

She took a breath and knocked on the door really quickly.

"Who's there!" they heard Hermoine call out.

"I need to use the bathroom." Said Mabel very quickly like someone who had to use the bathroom.

"What but…" said Hermoine.

"I don't care! I NEED IT NOW!" said Mabel, "I'm about to burst!"

Dipper looked at his twin sister trying not to laugh.

Hermoine opened the door and Mabel grabbed Dipper and pulled him inside.

Hermoine, Harry and their friend Ron Weasley were shocked.

"Wait! Were you following us?" asked Ron.

"We were." Sighed Dipper.

"Wait aren't you that kid who Pro. Flitwick let him eat Sugar Quills in class?" asked Ron.

"And Pro. Sinistra, Pro. McGonagall and Pro. Lockhart." Laughed Mabel.

"Mabel." Said Dipper.

"Oh you're that girls with the jumpers." Said Harry.

"Sure am!" said Mabel opening her robe so they see her sweater of the day which was yellow with the words "'Puff Pride" written in black.

"But that doesn't doesn't explain why you're here." Said Ron.

"Mason and Mabel were also researching the Chamber as well." Said Hermoine.

"You were?" asked Ron.

"Yeah." Said Dipper, "I was looking into what the monster could be, I haven't gotten much done yet, but I have figured out that is has to be a snake."

"really what makes you say that?" asked Ron.

"Considering that Slytherin's symbol is that of a snake. Not only that but Slytherin was a skilled Parselmouth." Explained Dipper.

"Honestly I can't belie I didn't think of it until I talked to them earlier." Said Hermoine.

"I haven't been doing much of the studying." Admitted Mabel, "I've just been helping him and make sure he doesn't choke on a quill."

"Mabel." Muttered Dipper blushing.

"So what are you doing here?" asked Ron.

"Whatever you're doing in here we want in." said Mabel.

"It's clear you could use the help with whatever your investigating." Said Dipper.

Ron looked at little unsure.

"I think that's an excellent idea." Said Hermoine.

"Why?" asked Ron.

"We're both Muggleborn." Said Dipper.

"Of course you can help." Said Harry relaxing why they would want to stop the thing.

Hermoine began to show them the book they checked out.

"The Polyjuice Potion?" asked Mabel.

"It's a potion that lets you to turn into someone else." Said Hermoine.

"Why are you using it?" asked Dipper very concerned.

"We want to get information from Malfoy." Said Ron.

"We think he's the Heir." Said Hermoine.

"I don't think he's the heir." Said Dipper.

"Really why?" asked Harry.

Mabel blew a raspberry, "If he was the heir he would be about bragging it all the time."

"Malfoy's just a jerk, but I don't think he's doing it." Said Dipper.

"Oh really what's your plan?" asked Ron.

"Study up on what the monster is and figure out how to protect ourselves." Said Dipper.

"But if we stop Malfoy from doing any of it." Said Ron.

"Wait." Said Hermoine, "We can do both."

"Really why?" asked Ron.

"You see the lacewings need to be stewed for 21 days, and the fluxweed need to be harvested at the full moon." She explained, "We have a month until it's ready."

"Oh you're kidding." Said Ron.

"What else does the potion need?" asked Harry.

"Well it looks like a lot of the ingredients we can get from the student stores." Said Hermoine.

"But some of them I don't think even get." Said Dipper.

"Unless we have to steal from Pro. Snape's private stores." Said Hermoine.

"Not to mention that we also need something from the person we want to turn into." Said Dipper.

"Wait you mean like toenail?" asked Ron, "I'm not drink Crabbe's toenail."

"It can be hair." Said Dipper, "Or skin… it doesn't have to be a toenail."

"He's right, don't worry it doesn't have to be a toenail." Said Hermione.

"I wonder if there's a way to mail order the ingredients through, the ones we can't get easily." Said Dipper.

"I didn't even think of that." Said Hermoine, "That's a great idea Mason."

"Dipper." Said Dipper.

"What?" asked Hermione.

"Call me Dipper." Said Dipper, "That's my nickname."

"Oh, okay." Said Hermoine.

"Why do they call you that?" asked Ron.

"No reason." Said Dipper adjusting his hat somewhat nervously.

"So I guess we're going to help each other then!" said Mabel.

Mabel proceed to pull Harry and Ron into a hug.

Harry and Ron looked at Dipper who just shrugged.

And so began a friendship between the five of them… one that would become a very important one.

Next Time: After Harry ends up in the Hospital Wing, he learns more about what's going on... right after the first student victim appears. What will happen find out next time!