Marco found the others all seated on the floor happily munching on Snookers bars from the pile in the corner when he returned. River noticed him and called out. "Ah, Marco, my boy! What did you find? Were you successful?"

Marco presented the brush to Dr. Doofenshmirtz. "Star's hair brush. Should be all the DNA you need in there."

"Perfect!" Dr. D. exclaimed, snatching it from Marco's hand. "That'll do the trick!" He grasped a hair protruding from the bristles of the brush and placed it on the tray beneath the analyzer. He turned back to the others. "Anybody got...a coin...of...whatever currency this machine takes?"

Janna raised an eyebrow. "Um...what for?"

"It's still a vending machine," Doofenshmirtz replied as if the answer should have been obvious. "It won't power up if you don't put a coin in it."

The Mewni natives checked their pockets. "Ah! Here we go!" Eclipsa handed a copper-colored coin to the scientist, who promptly fed it into the slot.

"Alright! Let's see where your friend is." He punched a sequence into the keypad and stepped back as the machine began to whir.

The analysis probe emitted a translucent ray of red light over the single hair beneath it. Everyone waited anxiously. After a few moments, the tiny screen that normally displayed the letter and number of the selected snack lit up, and Doofenshmirtz carefully studied the row of digits scrolling past.

"Well?" Marco asked hopefully. "Did it find Star?" Doofenshmirtz didn't respond. "Did it?"

The string of characters scrolled past a second time. "...Huh..."

Janna frowned. "Uh...Earth to Dr. D? Everything okay?"

"I, uh...I don't know how to tell you this, but..." He nervously wrung his hands. "It says your friend is...in the sky..."

"She's with Lilacia?" Eclipsa exclaimed.

Doofenshmirtz blinked, extremely confused. "Say what now?"

"Flying Princess Pony Head," Marco said flatly.

Doofenshmirtz stared. "...That is not clearing anything up for me."

"What are we waiting for?" River exclaimed, already breaking for the exit. "Let's go!"

Marco urged Dr. Doofenshmirtz along. "C'mon, I'll explain on the way."

As they hurried down the stairs to the Monster Temple's lowest floor, Janna asked, "Why did you seem so afraid to tell us Star was in the sky?"

"Oh, that. Heh. To be perfectly honest, I thought that meant she was dead."

Tom watched as Star anxiously paced back and forth, thinking that she was going to start wearing a rut in the ground if the man from the restaurant didn't return soon. When he did, Star just about crashed into him as she bounded over to him, bouncing up and down on her feet.

"Did you talk to whoever it was you were calling? Can they help us?"

The restaurant greeter chuckled. "I did. They said to give them at least a montage-worth of time and they'll have a solution for you."

Star ceased bouncing. "'A montage-worth of time'? What the heck does that even mean?"

He gave an exaggerated shrug. "Beats me."

Tom spoke up. "Not to pry, and, maybe it's not my place to ask, but who was it you called?"

"These two nice boys that visited here over the summer. A couple of real geniuses. They said they're happy to help."

Star raised an eyebrow. "And...how...exactly...are they going to help?"

The man shrugged again. "I'm not sure. But they said to 'keep an eye on the sky.' So...I guess do that!"

Star and Tom glanced at each other, equally confused.

With the group congregated at the bottom of the Monster Temple stairs, Janna turned her eyes skyward. The Mewni sky was amazing compared to that on Earth, with its pink hue and trio of moons visible at nearly all hours, and, high above, the fluffy layer of cotton-candy clouds that made up the Cloud Kingdom. "So how exactly do we get up to Pony Land without Magic?"

"It's a little bit difficult-" Moon began, but River cut her off.

"Yes! Difficult! But it is lots of fun!"

Before anything else could be said, Globgor clenched his muscles and grew to his largest form, which startled Perry and caused Dr. Doofenshmirtz to faint. He smiled down at the Earthian teenagers and winked.

Janna slowly nodded. "Ah, I get it."

The four-story high monster set his hand flat on the ground, palm up. River hoisted the unconscious Dr. Doofenshmirtz over his shoulder and hopped into Globgor's waiting hand with Marco, Janna, and Perry.

"Everybody ready?" Globgor's voice boomed as he slowly raised his hand off the ground.

"Ready for what exactly?" Marco started to ask, but he was cut off as Globgor's hand suddenly closed loosely around its passengers. The monster reared back his arm and gently tossed the three humans, one Mewman, and the platypus skyward.

Marco screamed while River and Janna cheered with excitement. Perry, on the other hand, quickly unfolded his hang glider. He nudged the glider to the left until Marco was close enough to grab ahold of the bar. Then he moved to the right to pick up Janna. River grabbed onto the lead edge of the wing with his left arm as he held Dr. Doofenshmirtz with his right, cheering as they crested the edge of the pink clouds on which the Cloud Kingdom rested.

The landing wasn't particularly smooth. The "ground" was springy and soft, and when Marco, the glider's tallest passenger, touched down, his shoe caught. His hands were yanked from the bar and he tumbled along the squishy ground. Janna's feet touched next, and this time the entire glider pitched forward and crashed into the clouds, sending its remaining passengers tumbling.

"Wooo!" River cried as he pulled himself upright, pumping his fists in the air. "What a rush!"

Janna chuckled, smiling broadly as she straightened her hat. "That was even more fun than boot sledding!" She looked to Perry, who was busily searching for his fedora. "Did you have that glider this whole time?"

Perry gave a brief nod.

"Where were you keeping that?"

Perry just shrugged.

Marco caught up with the others. He was carrying Perry's fedora. "Here you go, Perry." The platypus gave a grateful smile as he accepted the hat and pushed it back atop his head. "Is everybody alright?"

"We're good," Janna said, flashing a thumbs up. "The ground is really soft."

Doofenshmirtz's eyes flickered open and he raised himself to a sitting position. His fingers prodded at the squishy clouds beneath him. "Huh...that's different." He checked out his surroundings. Before him was an ornate gate flanked by hedges made of slightly lighter-colored pink clouds. The hedges surrounded the exterior of a castle who's purple walls also appeared to be made of cloud. "So...I'm guessing this must be the Cloud Kingdom."

"Astute observation, Dr. D," Janna quipped.

Marco bounced his way toward the gate, his feet sinking into the clouds beneath him with every step. "C'mon. Let's go find Pony Head. Hopefully Star is with her."

Star had never owned a watch, and as minute after minute ticked by and the sky overhead remained decidedly empty, she wasn't sure if she would feel better knowing how long it had been or not. She idly nudged a pebble around in the sand with the toe of her boot. "Ughhhh...how long do we just have to sit here?"

Tom gently squeezed her shoulder. "Be patient, Star. We'll get to Echo Creek. Don't worry."

Star let out a long sigh. "I know. I haven't seen Marco in this long...what's a little bit longer, right?"

"Exactly. You'll be reunited with Marco soo-"

Tom's voice was abruptly drowned out. Star's eyes went wide as she watched something spewing fire from its underside alight gently on the ground a few yards away. It was a rectangular prism made of gray steel. The rocket engine in its base which provided propulsion was completely concealed when it sat flat on the sand.

"Uh...What the heck is that?" Star whispered.

Before either teen could begin to speculate, the tall face of the box swung open, revealing an interior almost completely void of decorum. A screen set into the back wall was the only place the gray steel was interrupted.

"Uh...I guess...we go inside?" Tom said hesitantly.

"I, uh...I guess so."

With slow and hesitant steps, they approached the box. Star tapped the toe of her boot against the side, but nothing happened. They carefully stepped inside and nearly jumped out of their respective skins when the screen on the rear wall illuminated.

"Hello!" greeted a cheerful voice. It belonged to a young boy with the most peculiarly shaped head Star had ever seen on a human being. A second boy stood beside him, with two unequally sized eyes and a shock of green hair. "My name is Phineas, and this is my brother Ferb. Welcome to our Emergency Transport Rocket! It can get you anywhere in the world faster than you can say 'Liechtenstein lexicalizations'!"

The image of the two boys shrank into the corner of the screen, revealing a keyboard and blank text box. "Just enter your destination using the keyboard. You can enter the name of a city or landmark, a street address, or geographical coordinates. Once you hit enter, the rocket will launch and fly you to your destination in a matter of minutes. Happy travels!" Phineas and Ferb waved and the inset picture disappeared, leaving the keyboard on the screen.

"Wait, those two kids built this?" Tom asked aloud. "They look like they're ten!"

Star wasn't listening. Her heart was pounding as if it were trying to free itself from her rib cage. A trembling finger reached for the touchscreen and she carefully entered the only address on Earth that she still remembered by heart.

4815 Avocado Terrace, Echo Creek, California.

Her finger hovered over the enter key as she turned to Tom. "Not turning back now!"

Her finger tapped the soft key and the rocket door swung shut.

"Pony Head!" Marco's voice echoed down the long hallway. "Pony Head! Are you here?"

There was no reply save for the sound of their footsteps.

River cupped his hands around his mouth. "Dave! Where are you, you old scoundrel?"

"King Pony Head's name is 'Dave'?" Marco wondered aloud.

Doofenshmirtz was fascinated. "Boy, just when I thought we'd seen every weird place in the multiverse, we end up in a castle on a cloud! Pretty neat, huh, Perry the Platypus?"

Perry only shrugged. The little platypus didn't know what to think about anything anymore.

The hallway ended in a set of double doors that, unlike virtually everything else in the castle, were made of wood. Marco pushed them open and the group followed him through into a large, open room with a dining table serving as a focal point. There were no chairs around the table.

Janna whispered to Marco. "Do you know where you're going?"

He shook his head. "Nope. I've never been up here before."

River called out once again, his booming voice rattling the crystal chandelier over the table. "Hello?! Anybody home?"

"Pony Head?" Janna yelled.

"Pony Head? Lilacia?"

"Oh, I know I did not just hear someone call the princess by her first name!" came a voice from the top of the staircase. Flying Princess Pony Head herself appeared from the hallway, her face writ with annoyance, but her expression softened and her eyes went wide as she caught sight of her visitors. "Janna! Earth Turd! Some...weird...pharmacist-gargoyle-looking dude?"

"Oh, come on! Even the floating unicorn head in the cloud castle in another dimension thinks I'm a pharmacist?"

Lilacia zoomed excitedly down the stairs, halting before Marco and Janna. "Oh, my goo goo gracious! I never thought I'd see you guys again!"

"It's good to see you, too, Pony Head," Marco greeted, and the princess accepted brief hugs from her friends.

"Oh, my gosh, how did you guys get here from Earth?"

"It's a long story, and we'll explain later," Janna said. "We're trying to find Star. Have you seen her?"

"Star?" Lilacia raised an eyebrow. "I haven't seen her since she went to the Underworld with Tom, like, two weeks ago."

Marco felt as if his heart had come to an abrupt stop. No...it can't be...it ca-

Seeing the distressed expression on his face, Janna elbowed him in the ribs. "Don't jump to conclusions," she whispered quickly.

Pony Head went on. "She said they were going to Tom's creepy grandpa's study or something to look for a way back to Earth."

Marco and Janna's eyes met, their irises growing to the size of dinner plates.

"Star...was doing...the same thing..." Marco stuttered.

"As us," Janna finished.

Marco whirled around to face River. "How do we get to the underworld?"

"You, uh...can't, without a demon."

"Drat! How are we gonna get down there?"

"Marco?"

Marco turned slowly back to Janna.

"If Star and Tom were doing the same thing we were, and we made it back to Mewni, then-"

"-They might have made it back to Earth."

"Exactly."

Marco scrunched his lips together hard. He then addressed Lilacia. "Pony Head, Dr. Doofenshmirtz here built a tracking device to find Star, but it told us she was here."

"Well, she ain't here, so."

"There has to be something of hers here with DNA on it, otherwise the tracker wouldn't have led us here," Marco insisted. "Come on, Pony, think."

"Oh...you know what it probably is?" Lilacia looked embarrassed. "I may have kinda sorta stolen one of Star's brushes, like, six years ago. It's in my room, hidden under my mattress."

Janna nodded. "Yeah, that'd probably do it." She turned back to Doofenshmirtz. "Dr. D, is there a way we could scan for Star across all dimensions, not just this one?"

"Sure, I could do that. I just need a way to boost the power on the tracker."

What was supposed to be a friendly slap on the back from River accidentally sent the scientist sprawling onto the cloud-floor. "You just leave that to me! I'll get you all the power you need."

The interior of the rocket was very dark. The only illumination came from the screen, which showed a view of the clouds as they sailed past.

Star didn't think her heart had ever pounded harder in her entire life. Her arms physically trembled.

I'm so close...so close to Marco. I hope he's as excited to see me as I am.

Who am I kidding? Of course he is.

The trip was not long. The clouds dissipated as the rocket descended, and the Californian shoreline came into view. Star recognized the beach where she and Marco had spent that wonderful day together. A little bit further inland and they were sailing past more familiar sights. Star noticed the dog park, and the school, and the drainage canal. And then suddenly, the rocket was descending, gently lowering to the ground. The screen showed the view facing the street, but Star had seen that same brick ranch house on the opposite side of Avocado Terrace every day when she stepped out onto the front stoop of the most beautiful home on Earth.

The rocket engine let out a low whine as it switched off, and the box came to a halt. The door swung open, and Star and Tom shielded their eyes against the sudden brightness of the sun. When her eyes adjusted, Star found herself tearing up.

4815 Avocado Terrace.

It was so surreal it almost seemed fake, like some extremely realistic simulation or a vivid dream. Crouching down, Star ran her fingers through the grass, just to make sure it was real. The sharp edges of the blades of grass tickled her fingers and palms. She smiled as she stood up, tears welling up in the corners of her eyes.

"I'm...home..."