Okay, guys, we made it to book 3 of "Sonic Underground: Equestria Girls". If you'll remember, book 1 was pretty political, then book 2 was more musical, and for book 3, it's time to get athletic. Here's the rundown

When Rainbow sends everyone an emergency call for a guitar string of all things, Sunset sees someone messing with the portal. When this mysterious stranger turns out to be this world's Twilight, about to compete in the Friendship Games, Sonic and the others must stop her from stealing Equestrian Magic and ripping the Multiverse to shreds. Enjoy!

Ch. 1: Who was That?

It had been a year since the Battle of the Bands, and Sonic and his team were settling back into the swing of things on Mobius when suddenly Rainbow Dash called in over the interdimensional commlink's emergency channel. Quickly, everyone hopped through the vortex just as everyone showed up. Sunset was dressed differently than when Shadow first saw her. Now she was wearing a different jacket, a sky blue blouse with a canary yellow skirt underneath, jeans and high-heeled boots.

"I got your text, Rainbow Dash," she said. "Did something come through the portal? Is Equestrian Magic on the loose? Did Twilight come back with a problem that only we can solve?"

"Did another Mobian crook show up bent on taking over?" asked Sonic, drawing Caliburn, whom he had strapped to his back as Shadow pulled a couple of shotguns off his back that looked like those belonging to Reaper from "Overwatch".

"Has a giant cake monster covered all the cakes in the world in cake?" asked Pinkie Pie, shoving two cupcakes into her mouth at once.

"Pretty sure that would be a good thing," said Manic, brandishing a pulse pistol. "So any of those right, RD?"

"Um, not exactly." said Rainbow, picking up her guitar.

"Uh, I don't understand." said Sunset.

"Me neither." said Sonic, sheathing Caliburn.

"Well people," said Applejack, playing with a broken string on Rainbow's guitar. "I was just tellin' Rainbow Dash here that a broken guitar string doesn't really qualify as an emergency."

"It totally does," said Rainbow. Then everyone did an anime-style pratfall before Sonic got up really angry.

"Are you telling me you dragged my team across the Multiverse for a broken guitar string?!" he asked.

"Really, Rainbow Dash," said Rarity. "I was in the middle of sewing a very complex applique on my latest frock."

"And I was just about to tuck everyone in for the night at the shelter," said Fluttershy, snuggling a rabbit in the cool evening air. "Now we'll have to start stories all over again."

"The Freedom Fighter Emergency Line is only for reporting emergencies," said Tails. "So why bother sending us an emergency message for a guitar string?"

"Well, I was going to pony up and show our fans some awesome guitar licks," she said, gesturing to three younger girls on the stairs of the school. "But I kinda need all six strings to do it. Got any extra?" Everyone groaned until Sonic reached into his pocket and pulled one out.

"Here. It's made of vibranium, so it can't break no matter what," he said.

"Thanks." said Rainbow.

"But everyone finished practicing for the day," said Sunset. "I'm pretty sure all the music rooms are locked."

"No problem," said Rainbow. "The acoustics in the hallway are perfect for power cords." Then she let loose a strong chord on her guitar. "Cmon. Let's go."

"Sorry, we've got work to do back home. Tails?" asked Sonic.

"Can't. The portal cannon's flux capacitor is fried, and I can't exactly pick one up around the block," said Tails, throwing something metal into the nearby trashcan. "Looks like we're stuck here until I can build a new one from bits and pieces."

"Well, we might as well listen to Rainbow's performance." said Shadow as he and the others walked in.

"You coming, Sunset?" asked Applejack.

"I'll catch up in a bit," she said.

"I think I'll stay out here too. Keep her company," said Sonic. Applejack walked in and Sonic called his mother on the interdimensional coms, telling her they were trapped at CHS. Sunset pulled out her magic book and started writing to Twilight in Equestria.

"Dear Princess Twilight," she wrote. "How's life treating you in Equestria? Any cool new magic spells? It's been pretty quiet here at CHS since the Battle of the Bands. We still pony up whenever we play music, which Rainbow Dash just loves to show off, but I still can't quite grasp what it's all about. I would love to hear what you think about it when you get a sec. Your friend, Sunset Shimmer." Then suddenly a bus rolled up in front of the school and someone in jeans and a hoodie walked off just as it drove off.

Then she pulled out some sort of meter and walked over to where the readings were strongest, I.E., the portal to Equestria. She touched it and it started shining when Sonic noticed her.

"Hey!" he called and the person turned to him and Sunset. "What are you doing?" Quickly the person ran off. Sonic, knowing she hadn't seen him before, raced after her realistically enough not to raise any suspicions, with Sunset hot on his heels. Quickly, the person crossed the road. Sonic tried to follow her, but a car got in his way so he jumped over it and ran on the roof.

"Sorry!" Sunset said to the driver. Then, just as Sonic caught up to the person, another bus rolled in and she jumped on board before it raced off. Sonic, who tried to pounce on her, missed and landed on the ground. Soon Sunset caught up to Sonic as he pulled himself up.

"What was that about? Who was that?" asked Sonic.

"I don't know. But the others might. Cmon," said Sunset as she and Sonic raced back into the school.

On the bus, the girl revealed herself to be this world's Twilight Sparkle. She sighed in relief at not being caught. Soon she arrived at a school that looked like it was built out of crystals, and made her way to a small private laboratory in the back. There, she took apart her meter and made it into some sort of high-tech-looking necklace.

Ch. 2: Friendship Games?

The next day, the Canterlot High library was busy as ever with Sunset and the others looking for something that might explain the girl from the bus.

"She was defiantly doing something to the portal," said Sunset.

"And if she didn't, she was gonna," said Sonic.

"Do you think she came through the portal from Equestria?" asked Fluttershy.

"Nah. Pretty sure we would've noticed that," said Sonic. "And I'd know for sure if she came from Mobius with me and the others."

"I think she's actually from over here," said Sunset.

"Well, that's a relief," said Applejack. "The last thing we need is another magical so-and-so bent on world domination coming over from Equestria." Then she winked at Sunset, who was totally over it.

"Agreed," said Rarity. "I have no interest in another fight against the powers of dark magic. The wear and tear on my wardrobe is just too much to keep up with."

"Still, a mysterious figure snooping around the portal?" asked Sunset. "Don't you wanna know what she was up to?"

"I know I do," said Silver.

"I don't even wanna guess." shuddered Fluttershy.

"Well, ya don't have to. Because I totally figured out who it was," said Rainbow, rounding the corner with a yearbook.

"Ooh, ooh!" said Pinkie, somehow pulling out books related to topics she said. "A nighttime statue cleaner? A magical portal maintenance maintainer? A gardener?"

"You guys actually have books on magic portal maintenance?" asked Shadow.

"This is Canterlot High. We've got books on practically everything," said Applejack.

"Even genetic engineering?" asked Shadow.

"Except that," she replied.

"Thought so," said Shadow.

"Yeah anyway, seeing as how they got off a bus from the city, and then got back on a bus headed to the city, I'll bet they go to…"

"Crystal Prep," said the girls disappointedly.

"Yep," said Rainbow. "With the Friendship Games starting tomorrow, they'd totally try to punk us by defacing the Wondercolt statue."

"'Friendship Games'?" asked Sonia. "What are those?"

"A series of events our school competes in to try and win a crazy prize." said Applejack.

"Sounds a lot like the Olympics," said Sonic, remembering his years going up against Mario and his team in the Olympics in London and Sochi. "Can't wait for Rio," he thought.

"Anyway, why would someone take a bus all the way from the city for that?" asked Sunset.

"Because the Crystal Perp Shadowbolts are our biggest rivals?" asked Applejack.

"Because that's just what the students at Crystal Prep would do?" asked Rarity.

"Because even though they beat us in everything…" said Rainbow, showing them pictures of the Wondercolts losing at everything. "Soccer, tennis, golf; They still have to gloat." Then she showed them a picture of the Wondercolt statue dressed up like a clown.

"Seems kinda stupid, if ya ask me." said Manic, resting on top of a bookcase and spinning his drumstick on his hand.

"STUPID?!" asked the girls, causing him to fall off.

"OW!" he shouted when he landed.

"So I guess you think the Friendship Games are stupid too?" asked Rainbow.

"Well, look on the plus side; It's not like we'll be fighting the powers of evil magic." said Sonic.

"No," said Fluttershy. "We'll be fighting against a school full of meanies. Not everything has to be magical to be important."

"Yeah, I guess you're right," said Sunset. "We're sorry. We know it's a big deal."

"That's putting it mildly, darling," said Rarity. "They're still revamping the playing field out back in preparation."

"How long has it been going on?" asked Sonic.

"About five weeks," said Rainbow. Sonic quickly whistled in amazement.

"You guys take these things really seriously, huh?" he asked.

"I just don't understand why there's this whole rivalry," said Sunset. "Aren't the 'Friendship Games' supposed to be about our two schools getting along?"

"Well, it's kinda hard to get along with someone who beats you at everything," said Applejack.

"Not anymore," said Rainbow, tossing the yearbook away. "This time, things are gonna be different."

"How so?" asked Shadow.

"Oh, you'll find out." she said.

"Why does that not fill me with confidence?" asked Sonic.

"And here I thought dragons were the only ones who could be ridiculously cryptic." said Manic.