Shaggy and Scooby were still running for their lives.

"No one said anything about boogeyman!" Shaggy said.

"Or rhosts!" said Scooby.

They were so scared, they didn't see three werecats coming their way.

CRASH!

Shaggy and Scooby collided with Toralei and her werecat sisters.

"Mrow! What the fang?!" Toralei screeched.

Scooby gasped seeing the cat girls. "Rats!"

"Who are you calling rats, Dog face?!" Toralei snapped.

Scooby growled.

"No, he said cats, not rats!" Shaggy corrected.

The werecats flashed their eyes at Shaggy. "Is that mutt yours, normie?"

"Uh..." Shaggy backed away as the monster cats started to gang up on him.

But Scooby got in between them. He growled at Toralei.

Toralei and her posse hissed and snarled and went all wild cat on Scooby.

Normally, this type of thing would frighten Scooby, but with his canine instincts overpowering him, he leered his eyes and barked.

And he just kept barking.

Toralei and her group stopped as this apparently brave dog wasn't scared. Scooby lurched towards them, they started to back away slowly.

Now the werecats were scared. "Normie! Control your dog!" Toralei said to Shaggy.

Scooby lunged. The ghouls screamed and started to run.

"Scooby Doo! STOP!" Shaggy cried as he chased after his friend.

Velma and Frankie came out of the ghouls' locker room. "Aside from those claw marks, there were no other clues." said Velma.

"Well, so far, Toralei is our first and probably only suspect." said Frankie. "I can't think of anyone else

MROW! ARF! ARF! ARF!

"What was that?!" Velma gasped.

"Sounds like a cat and dog fight!" Frankie guessed.

The girls paused.

"Cat?!" Velma said. "Toralei!"

"Dog?!" Frankie said. "Scooby!"

The teens took off.

Meanwhile, Draculaura, Operetta, Daphne and Fred were following the meows and barks.

"I just knew Toralei was behind this!" Draculaura said. "She's gone too far this time!"

"She's gonna run out of nine lives when I'm done with her!" Operetta growled.

In the midst of all this chaos, there was one section of the hallways that was completely still and quiet.

Peeking from around the corner, a student in a purple dress poked her head out and looked around

She was a harpy. Her body was covered in neon green feathers and her head feathers and wings were dark green.

The harpy's red eyes twinkled as she scurried to her lockers, she looked over her shoulder a few times before opening the door.

"OUT OF THE WAY!"

"Huh?!"

BAM! CRASH!

The harpy was tackled by three werecats and a Great Dane. Her locker door swung open and piles of shiny trinkets poured out.

Shaggy came on the scene. "Zoinks! What happened here?!"

Velma and Frankie arrived. "What the-?! Hey! That's my bracelet!" Frankie said. "And there's Cleo's nail polish! And Clawdeen's jewelry!"

"It's everyone's stuff!" Velma said.

"Hey! Check out the groovy watch!" Shaggy picked up a wrist watch and tried it on. "What do you think, Scoob?"

"Unhand that watch, thief!" said a disembodied voice.

Shaggy screamed when something grabbed his wrist. The watch slipped off his hand and it was floating.

"Mr. Where?!" Frankie gasped.

"That's right." Mr. Where became visible. "And it seems I caught the thief in action!"

"What?! Like no way, Mr. Where! I just found it here! Honest!" Shaggy insisted.

Scooby popped his head out from the pile. Hanging around his nose were Clawdeen and Howleen's jewelry.

"Aha!" So, what else have you two been smuggling?" Mr. Where interrogated. He went invisible again.

Shaggy gulped. "Uh...where did he-" His eyes went wide. "Ahahahahahahaha!" Shaggy felt something tickling him. "Hahahahahahahahahaha!"

Then Scooby started laughing. "Reeheeheeheehee!"

Mr. Where was using his invisibility to search the boy and dog's person, unintentionally tickling them.

"Mr. Where! Stop!" Frankie grabbed his arm, or, at least what she thought was his arm.

"Miss Stein." Mr. Where said after a pause. "Should you release my head please?" He became visible and Frankie gasped seeing that she was clutching Mr. Where's head.

Fred, Daphne, Draculaura, and Operetta came and gaped at what they were seeing.

"What the heck is going on here?!" Fred said.

"We found Shaggy here with my watch!" Mr. Where held up the evidence.

"I didn't take it! Scoob and me didn't take anything! I swear!" Shaggy said. "The last thing we'd do is steal from monsters!"

"Reah!" said Scooby.

"EVERYBODY STOP!" someone squawked.

The monsters and humans and dog went silent. They slowly moved their heads to the harpy girl.

"They didn't take your things," she lowered her head. "I did."

"Harper?!" the ghouls said.

Mr. Where cocked his head back. "Ms. Talyntino?!"

"Who?!" Velma said.

"Her name's Quill Talyntono. But we call her Harper." Draculaura said.

"It's a bird lady!" Shaggy said, pointing at her.

"She's a harpy, Shaggy." said Frankie. "And that explains why she's been taking our stuff. She collects shiny things."

Harper sighed.

"What? Lots of people assume that birds steal shiny objects, but that's only classified as a myth." Velma informed.

"That's because harpies started that myth." Harper admitted. "I've been collecting shiny things as far back as I can remember. It runs in my family."

"So it really was Harper all along!" Operetta said. She reached into the pile and took out her favorite guitar pick.

"Then those claw marks in the theater were from your talons!" Mr. Where said.

Harper looked at her hand, her nails were just as sharp as Toralei's claws. "Yeah, I just got a manicure. I'm sorry, everyone. All that stuff I found were just things lying around the school. Once I saw them, I couldn't help myself. I didn't mean to make such a mess of things..."

She was going to walk away until Frankie grabbed her shoulder. "It's okay, Harper." The Franken-ghoul smiled. "But you need to have self-control. So next time you see something laying around, turn it into the lost and found, okay?"

Harper smiled back. "Okay, I will."

"Besides, it looks like everything is here and accounted for." Mr. Where said, observing the locker of shiny trinkets.

"What a story!" Spectra appeared through a locker. "The mystery of the Monster High thief is solved!"

Twyla came out of the shadows. "That was some show you guys put on." she told Shaggy and Scooby, who yelped and shivered with fright.

"Come on, don't be like that." Twyla said with a half smile. "Bogeymen aren't as mean and scary as you think they are."

"The same goes for ghosts." Spectra added.

Shaggy and Scooby looked at each other. When they finally thought about it, the monsters here never really meant no harm.

"Y'know, I guess we were spooked for nothing, Scoob." said Shaggy.

"Agreed." the Great Dane couldn't agree more.

After that, a line formed in front of Harper's locker.

Above it was a huge sign that said; 'Lost and Found'

"Well, gang, another mystery bites the dust." said Fred.

"Thanks to Shaggy and Scooby nonetheless!" Daphne said.

Velma gave Shaggy a pat on the back. "I knew you guys had it in you...somewhere."

"MYSTERY INC.!" a commanding voice shattered the tranquil.

Marching towards the teen sleuths was Headmistress Bloodgood. They braced themselves as she approached them with a withering glare.

Shaggy gulped, Scooby covered his eyes.

The headmistress smiled. "Good job, children. Thank you for finding the thief."

"You're welcome, Headmistress." Velma said.

"And sorry for breaking in your office." Fred said.

"And into your school." Daphne included.

Bloodgood shook her head. "On the contrary, if it weren't for you wonderful, meddling kids, everyone's things would have gone missing for good!" She took out a silvery tube of lipstick. "I've been missing this for weeks! It's my favorite shade!" She opened the tube and applied the red lipstick on her already red lips.

"And thanks so for all your help!" Frankie said. "You guys can come back to Monster High anytime!"

"Well, I think we're going to be here at Monster Hugh for a while." Fred said. "We still have to fix the Mystery Machine!"

"Say no more!" The teens saw Clawd Wolf and Deuce Gorgon come in carrying toolboxes.

"We fixed your can for you, dudes." Deuce said. "It's all ready to go!"

"Like, wow! Thanks, guys!" Shaggy said.

"Reah! Ranks!" Scooby said.

Deuce shook his head. "Don't thank us, thank Mr. Where. He saw your van outside while he was investigating and asked us to fix it."

"Really?!"

Mr. Where appeared. "Really. And I apologize for accusing you, boys. I was wrong."

"Aw, it's okay, Mr. Where." Shaggy said. "That can happen to anyone."

"Reah, it's all good." Scooby jumped and gave the invisible drama teacher a lick.

Fred snapped his fingers. "We're back on the road, gang!"

The gang piled into their van and liked back. All the students and teachers were waving goodbye.

"Bye, guys!" Frankie shouted.

"Come back soon!" Draculaura yelled out.

"We will!" Shaggy said, waving back!

"Rye!" Scooby waved.

The Mystery Machine drove away. "This mystery was definitely one for the books!" Fred said.

"That's for sure." Velma said. "To think, that not only monsters are real, but they go to school like us!"

"Not to mention have killer style!" said Daphne. "Clawdeen and I came up with some great fashion designs together!"

"Yeah, I guess not all monsters are bad." Shaggy said.

As they drive, the gang all started to have a strange feeling. And they all felt the same feeling.

"Guys," Daphne said. "does this change anything? About us solving mysteries?"

"Of course not." said Velma. "Just because monsters are real, doesn't mean we're done with mysteries. Sure, there are good monsters, but there are lots of people out there impersonating ghosts and monsters for nefarious schemes."

"And wherever they are, we'll be there to take them down!" Fred said.

"As a team!" Daphne added.

"And best friends for life!" Shaggy said.

"Scooby Dooby Doo!" Scooby howled as the gang drove off to wherever the road takes them.