Deep in the darkest part of the Cloudsdale weather factory -- where the rainbows are made -- a pegasus flew through one of the hallways. Dark red, wet patches covered her fur and feathers as well as the white employee coat that she wore. Reaching her destination, she pushed the door open, and was greeted by a high-pitched shriek.

"What the hay, Wind Tunnel?" the stained pegasus growled, rubbing at one of her ears with a hoof to try and stop the ringing.

"Sorry, Star," the stallion said as he moved to stand up from where he fell onto the floor. "It's just that suddenly having you standing there looking like... that..." he motioned a hoof at her.

"Have you been reading that stupid book?" Star Glow asked, eyes narrowing.

"It's not stupid," Wind Tunnel retorted.

"Oh, come on." Star rolled her eyes. "Using ponies to make rainbows? It's ridiculous!"

"Okay, so the premise is a little out there. Still, there's more to it. It's all psychological. It's abou-"

"Whatever," Star Glow said, holding up a hoof. "I don't care. Anyway, I fixed the leak in the red tanks... again. I swear it breaks down more than any other color."

"Maybe," Wind Tunnel said in an ominous tone, "it's from all the po-"

"If you finish that," Star Glow snapped, "so help me, I will cram that book so far down your throat, you'll be burping letters for days!"

"Ha!" Wind Tunnel retorted. "Jokes on you. I can already burp the alphabet."

The mare glared at the stallion, saying nothing.

"Okay, okay." He held up his hooves. "I get the point."

"Attention rainbow maintenance department," a voice called out over the sound system. "There is a blockage in the main line that needs to be seen to immediately. Please report at once."

"Ugh," Star Glow groaned. "A main tunnel blockage. I hate those." She smirked as she narrowed her eyes at Wind Tunnel. "Guess it's a good thing that I'm not the one that has to deal with it."

"What?" Wind Tunnel squeaked out. "No. Please. Come on. I'll do anything."

"There is nothing you could do that I would want." She crossed her front legs. "Besides, I took care of the leak, so it's your turn."

Wind Tunnel let out a sigh.

"Fine," he conceded. "I'll be back as soon as I can. Don't lay a hoof on my book." He gave her a warning look before turning and heading out the door.

Glow Star watched him go then gave a shake of her head. Her gaze then turned to the desk and the book setting on. One of her wings flicked out, knocking the book off the desk and into the trash can.

"Oops."

Meanwhile, Wind Tunnel was making his way through the factory, grumbling to himself. He did not like having to deal with leaking tanks, but he hated dealing with clogged lines more. He really needed to find a position than in the maintenance department.

The pegasus made his way up to the main pools and looked around. The flow to one of the pools had stopped, little more than a drizzle coming from the end of the pipeline.

"How long has it been like this?" he asked a nearby pegasus.

"I don't know," the other responded. "We just noticed it when the feeder tank began to overflow."

Not too long then, Wind Tunnel thought. Normally the feeder tanks were kept pretty close to full, so it would only take a few minutes for them to reach the point where they would begin to overflow. Until it was fixed, the individual rainbow colors would need to be redirected to the other feeder tanks to run into the other pools.

With a flap of his wings, Wind Tunnel lifted off the clouds and glided toward the pipe. Gripping the sides as he reached the opening, he took a look inside.

The fact he was able to see inside to begin with was disappointing. He had been hoping that the problem would be here, which would make it easy to deal with: he could just give it a hard yank. It would damage the clouds around it a little, but not enough to prevent the rainbow liquid from flowing into the pool. So the blockage would be dealt with and the clouds would be replaced by the end of the day. Instead, he was going to need to figure out where the blockage was, and possibly how to remove it from somewhere in the middle of the pipeline.

Wind Tunnel moved to fly low along the length of the pipe, stopping every so often to tap it with his hoof and listen. Each time it sounded like an empty echo, he would fly further along and try this again. The pegasus kept going higher and higher up the line, stopping as he reached the base of the feeder tank.

It was a good news, bad news type of situation from what he saw. The good news was that he probably would not have to figure out how to get the problem out of the pipe, because it was probably at the bottom of the tank. The bad news was that it was at the bottom of the tank, which meant he would have to dive in there to get it. He was a pegasus, not a sea-pony.

After making his way to top, Wind Tunnel found a spot to land. Quickly, he took off the hard hat and the white lab coat. Next he grabbed a pair of swim goggles and put them on. Slowly, he took a moment to prepare himself, closing his eyes and taking several slow, deep breaths. Finally, he took a breath as big and deep as he could, and dove into the tank.

It was difficult to see through as numerous colors churned and swirled around him. He kept his wings close, flaring the edges out slightly to help with stability and guidance. He kicked and stroked with his hooves, working to make his way down toward the bottom. It was tough since his body naturally wanted to return to the surface. Granted, this was not a common event in the factory, but times like this made him wish they had some sort of weight system to help pull him down.

Finally, Wind Tunnel was able to feel the bottom of the tank against his hooves. With it, he knew which way to go. He gave a push off the sides and followed the slope of the tank's bottom to make his way toward the middle.

As he reached the spot the drain was suppose to be, he felt his hoof strike something. He gave a hard push to get closer to the bottom and grabbed at the object with his front hooves.

Tried to grab it at least. Whatever it was, the surface of it was extremely smooth and round. He could not get a good hold of it just by grabbing onto it with his hooves. It felt like it was a ball made of stone. It also seemed to be heavy.

Wind Tunnel gripped it, wrapping all four of his legs around the stone and pulling it tight to his body. Spreading his wings wide, he gave them a hard downward flap. It was enough to lift the stone for a moment, only to be pulled back down by the suction. He flapped again, being able to lift the stone off the drain before being sucked back into place again.

With no other choice, Wind Tunnel let go and swam back up to the surface. As soon as he broke through, he let out a massive gasp, replacing all the air he had lost. Quick as he could, he made his way to the edge and held on, trying to catch his breath.

"You," he pointed at a nearby pony. "Go let Star Glow that I need her help."

The pegasus nodded and ran off.

"Somepony bring me a crowbar," Wind Tunnel called out. "Whatever is down there, I can't get it out of there on my own."

He shifted to look back down into the pool of swirling rainbows. What in Equestria was it, and how did it get in there?