One evening at Canterlot High School, Mr. Greenhooves the school groundskeeper was just about ready to call it a night when he finished his night work.
"Well, time to pack it in." he said, before grabbing some of his supplies.
When he went to grab a rake, he didn't realize the school's hose faucet turned by itself causing the water to flow out.
"Huh? I thought I turned it off," Greenhooves said to himself before turning it off. He went to grab the rake again only to hear the water flowing again, "Dang nabbit." he turned it off again, only to see it turn itself much to his surprise and confusion.
"What the?" he suddenly saw shadows above him. He looked up and saw his gardening tools like his hedge clippers, rake, and little shovels hovering above him, "This ain't real!" he gasped, as the tools tried to attack him.
Greenhooves ran from them all the way to the school's back door. Using his keys he got inside and locked it from the inside.
"What was that about?" he asked himself in shock. Suddenly he heard an eerie moan coming from the dark halls, "Hello? Is somebody there?" He continued to hear the moan, "Hello?" he looked around getting paranoid by the second.
Just then the locker doors opened and stuff inside the lockers started flying out all around. Greenhooves panicked and started running down another hall with the lockers still flying open and their contents inside were pelting him.
Greenhooves tried shielding himself with his arms, but to no avail. When he came around another corner he saw something green and glowing before him. He screamed in a panic as things went dark.
The next day, CHS's seven top students were on their way to school. They were Sunset Shimmer, Fluttershy, Rarity, Rainbow Dash, Pinkie Pie, Applejack, and Twilight Sparkle.
"You girls ready for the big trig exam?" Twilight asked.
"Please don't even mention it." Rainbow groaned.
"Ya know you could've studied some more than your usual five minutes." Applejack suggested.
"You know 'study' and 'I' don't mix." Rainbow replied.
Sunset looked ahead seeing a crowd of students surrounding the school along with some police cars, and an ambulance.
"What's going on over there?" she wondered.
"A party that I wasn't aware of?" Pinkie gasped.
"What kind of party would involve cops and an ambulance?" Rarity asked rhetorically.
"A super duper special party!" Pinkie grinned.
They arrived at the crowd, as Twilight spoke to Flash Sentry, "Flash, what's going on here?"
"Mr. Greenhooves was found passed out in the school. The whole hallways have been trashed." he explained.
"Any idea who's done it?" Applejack asked.
"No idea." Flash admitted, until they saw some medics taking Greenhooves away on a wheel stretcher.
The girls made their way close enough to hear him, "I'm telling you it was a ghost that did this! He wants to rule the school!" he cried, before being put in the ambulance.
The students were concerned, until Principal Celestia and Vice Principal Luna approached, "Students, in light of these events school will be closed until further notice." The Principal began.
Many of the students while ecstatic to hear they could go home, were still concerned about what happened. Vice Principal Luna spoke up, "And no one is to go inside the school until this is all sorted out."
With that the CHS students started taking the leave to either go home or elsewhere. The seven girls however were curious about this, and snuck past the two sisters and went inside the school.
They saw just the way Flash described it. The hallways were littered with papers, books, and another stuff from the students lockers.
"Would you just look at this place," Rarity gasped, "What a mess!"
"Such vandalism." Fluttershy said in shock.
"You don't think what Mr. Greenhooves said is true, do ya?" Rainbow asked the group.
"About it being a ghost? No way." Twilight replied.
"Sunset, are their ghosts back in Equestria?" Applejack asked the former pony girl.
"Of course not. Despite being a land of magic, ghosts don't really exist there. It's all just scary tales made to teach kids not to poke around into stuff they shouldn't bother with."
Twilight sat her backpack down and out came Spike her dog granted the ability to speak through Equestrian magic.
"Spike, sniff around and see if you smell any unusual scents." she ordered.
"Sure thing, Twilight." Spike started sniffing the floor. The girls waited for some results, until Spike pulled his head up.
"Find anything?" Twilight asked hopefully.
"Nothing aside from the usual smell of sweaty gym bags and cheap hair gel." Spike answered, and the girls sighed.
"Well, that's no help." Rarity said.
"Hey, girls, look at this." Pinkie called.
The group went over to Pinkie Pie who was standing near a wall, "What is it, Pinkie?" Rainbow asked.
"Look." she pointed to the wall.
They saw a green stick gooey blotch on the wall, "What is that stuff?" Sunset asked.
"Green jelly?" Pinkie suggested.
"I don't think so." Applejack answered.
"Then what is it?" Fluttershy asked.
"Whatever it is, it's repulsive." Rarity gagged.
Twilight looked into her vest and saw her old magic containment device was glowing and pointed it in the direction of the blotch. She saw Pinkie ready to poke her finger at it, until she called, "Don't touch it!"
Pinkie pulled her hand back and looked at Twilight, "Why not?"
"That could be dangerous." Twilight answered, as she held up her device.
"Why're you still carrying that thing around?" Rainbow asked in confusion.
"Won't it take our magic again?" Fluttershy asked in worry.
"Don't worry, after that incident I reconfigured the device strictly into a tracker of supernatural anomalies. And this stuff is pulsating with it," Twilight explained, "I need a sample of this." She took out a little tool kit from her backpack and used a pair of tweezers to pull a sample from the blotch and place it inside a little zip lock bag.
"What now?" Spike asked.
"Let's get this sample back to my place so can study it." Twilight said, as they slipped out of the school without the principals or cops noticing them.
At Twilight's place, the brainy girl opened the door of her garage to reveal it was actual a miniature lab where she first studied the abnormal occurrences at CHS after the Battle of the Bands before moving it to her little room at Crystal Prep.
"Nice set up." Sunset admitted.
"Thanks. Sorry if it's a bit messy."
"It's decent enough." Rarity answered, while cleaning off a chair.
Twilight took the green slime sample she got and started running some tests on it. The girls waited as Twilight did research while occasionally passing her some supplies she needed. After about an hour of experimenting, Twilight turned to them.
"Girls, I think Mr. Greenhooves was onto something."
"What're you talking about?" Applejack inquired.
"The ghost thing."
"What?" they asked in disbelief.
"You don't actually believe that, do you?" Rainbow asked.
"I almost didn't, but this results proves it," Twilight went to her computer, as he friends watched her pull up a file, "This sample I got is actually ectoplasm."
"The stuff that is commonly found on ghosts." Pinkie finished, as the girls looked at her, "Years of monster movies." she grinned.
"So if it is a ghost..." Rarity shook.
"Then the school is haunted?" Fluttershy trembled.
"So it seems." Twilight concluded.
"Well, this is a problem," Rainbow spoke up, "The school is being haunted by a poltergeist."
"What're you so shocked for?" Applejack asked, "With all the stuff we've dealt with, this shouldn't be too surprising."
"Still magic is one thing, but ghosts? What can we do, hold a seance and communicate with it?" she asked rhetorically.
"Great idea, I'll go get my board." Pinkie was about to rush off, only for Sunset to pull her back.
"Hold it, girls. Let's not rush into things here. If this truly is a ghost we shouldn't try going after it without a thought up plan."
"What do you suggest, Sunset?" Rarity wondered.
"I'm not sure, but maybe Princess Twilight can help us." Sunset said, as she pulled out her magic journal.
"Let's hope she can get back to you faster than last time." Rainbow reminded her of Princess Twilight unable to come due to being stuck in a time loop.
"So do I." Sunset agreed, as she started relaying a message to Princess Twilight. After finishing her message, the group waited and hoped their friend from Equestria would respond.
When the book glowed, Sunset opened it up and checked her message, "Sunset, this ghost haunting the school sounds serious, and must be stopped. I'm afraid I alone can't help you in dealing with it," the girls looked disappointed, until Sunset continued, "But I can however bring some old friends of mine to your world and help deal with the ghost problem. Just head back to the portal at the school and wait for further instructions." she closed the journal.
"Twilight knows someone who can help us?" Rarity asked.
"That's what she says." Sunset replied.
"I wonder who they are?" Applejack wondered.
"Yeah, who's she gonna call?" Pinkie asked, as the group turned to face the fourth wall.