It stopped raining, and the Tortuga was in the park again. Bite-Size shivered in fear in his bat box.

"Storm's over, Bite-Size. You can come out now," Koki told him. The little brown bat peeped out of his bat box.

"Thank goodness," he sighed in relief. "That was scary with all the lightning and thunder."

"I know how you get about thunderstorms, my friend. But you're safe inside."

"And like they always say: 'There's a rainbow after every storm!'" Martin exclaimed, opening the screen windows. Outside, there was a long, colorful rainbow in the sky.

"Wow, Aunt Iris really outdone herself this time," Mina commented in amazement.

"I heard that there's a pot of gold where the rainbow ends," Jimmy said. "And I also heard about double rainbows."

"Double rainbows are really rare," Chris informed him. "And a pot of gold... after meeting Mina, I'm not sure on that one." Mina laughed at that.

"Well, the pot of gold part is false," she explained, "but Aunt Iris does put something at the end of all her rainbows."

"Cool! It would be fun doing a rainbow hunt!" Martin suggested, jumping of excitement.

"Then last one there's an unlucky leprechaun!" Chris shouted before dashing out the door.

"Hey, wait for me!"

"I'm not going to be unlucky!" Jimmy called out, following them.

"And neither are we!" The girls exclaimed before going in pursuit. Bite-Size flew after everyone. Martin and Chris were already neck and neck and heading down the hill.

"I'm gonna win, lil' bro!" Martin told his younger sibling.

"Not today, bro!" Chris responded, sprinting with all his might. Martin put all his leg strength to stay next to him. The end of the colorful arch came into view. "I see the end!" He pulled out a pair of binoculars. "I can't tell what the item is! The rainbow's too bright! But it's pretty big!"

"And I'm gonna beat you to it!"

"Oh no, you're not!" Unfortunately, Chris tripped over a rock he didn't see and instinctively grabbed Martin's shirt as he fell. Both brothers rolled down the hill in a tangled ball. An exposed ramp like rock was in their direction and they shot through the air and through the rainbow. When they landed, they tumbled for a bit before coming to a complete stop. They collapsed on their backs. "That... wasn't part of the plan."

"Definitely not." That's when they realized their voices... weren't their respective ones.

Chris and Martin gasped as they looked at each other. Chris had Martin's blue eyes and Martin had Chris's hazel eyes. Not to mention that their shirts had swapped colors. Their voices remained the same in their bodies, though.

"Chris?"

"Martin?" They shivered before they snapped out of it.

"AAAAAAAAAAAHHHHHH!" they screamed in panic.

Having returned to the Tortuga, the swapped brothers were pacing in panic around the control room. The rest of the crew could only watch in worry.

"This cannot be happening. This CANNOT be happening!" Maris (Martin/Chris) squeaked in Chris's voice.

"This isn't happening. This ISN'T happening!" Chritin (Chris/Martin) said in Martin's voice.

"Guys, you need to calm down," Aviva tried to assure them. "Luna is right now asking Iris how to reverse your apparent 'body swap'. She should be back in a little bit." As if on cue, Luna came in through a portal. Both brothers immediately went over to her.

"What did she say? What did she say? WHAT DID SHE SAY?!" they both panicked, startling the owl.

"Um, well, Iris had told me that this wasn't the first time this happened. There were many times that people swapped bodies by crossing her rainbows." she explained. "And every rainbow has an hourglass in case of this sort of situation. Did you get it before the rainbow disappeared?"

"Right here," Koki answered, showing a gold framed hourglass with golden sand. A little of the sand was already on the bottom. "It was just where the rainbow ended. Is it some kind of enchanted hourglass?"

"Very enchanted. It counts down the time the sun is up. The Kratt Brothers will have to cross through another rainbow before the all the sand runs to the bottom, or else..."

"Or else what?" Maris asked with a worried tone.

"You'll be stuck as each other... forever." Everyone gasped.

"FOREVER?!" the Kratt Brothers shrieked.

"Yes."

Both siblings fainted.

"How will we find another rainbow in that amount of time?" Mina asked.

"Any refraction rainbows will actually work. It just needs to be big enough."

"Refraction?"

"What's refraction?" Bite-Size asked. Chritin just kept biting his fingernails, fearing not returning to his body while Maris was about to cry.

"It's when a wave is bent when it enters a medium where its speed is different," Koki said, looking up the information on the monitor. "Basically speaking, the subject is bent to look different because its speed changed. When light is refracted, it splits into the seven colors of the rainbow. That's what rainbows are according to science: refracted light."

"And that's why they appear after it rains," Aviva added. "The light is refracted by the raindrops and creates an image."

"Yeah, Aunt Iris works along with Grandpa Zeus and Uncle Helios. When Grandpa makes it rain, sometimes Uncle Helios shines his light as well, so Aunt Iris joins them to create a rainbow," Mina explained.

"You think we can use these theories to help the Kratt bros?" Bite-Size asked.

"It will take a while, but we'll find a way of helping them. Till then, you guys will have to deal with this," Aviva said. Chritin and Maris stared at each other, gulping.

"Oh, guys, it's almost time for our Training session," Mina noticed. "We better hurry up."

Outside the Tortuga, close to the frogs' lake, the team prepared itself for training.

Chritin and Maris grabbed their respective medallions before joining the others outside. However, things didn't quite work out because they weren't even working!

"Hey, is something wrong with my medallion?" Chritin asked, looking at the jewels in his.

"Mine too," Maris followed.

"Maybe it's because you're not in your respective bodies," Mina theorized. "Try switching and we'll see what happens." Hesitantly, the brothers swapped medallions.

"Now we're talking!" Maris observed the medallion glowing.

He then tried to make a vine grow, but nothing was happening. "Huh?" Then he thought about how much concentration Chris has to do. Focusing on making a vine made his head hurt a little. He wasn't the thinking brother after all. A vine about a foot long came out of the ground. Maris smiled at this.

With Chritin, he just simply thought about it and a stream of water came flying by his head. Unfortunately, he wasn't used to this and the stream hit Koki, flattening her hair.

"Whoops, sorry Koki," he apologized. The swapped younger brother looked at the blue medallion. "So just thinking about it, even briefly, triggers it."

"That's possibly because mine reacts more to emotion than thought. So you be careful of what you think about."

"And you have to take it slow. Try making grass grow quickly first, then try on vines," Chritin recommended.

"Okay." Maris put a hand on the grass and focused. Almost instantly, the grass became two inches taller. "Yes! I did it!"

"Nice job bro. Now it's my turn." Chritin relaxed and simply flexed his wrist. Water began to circle around it like it was a giant ring. Chritin smiled and with a single finger, made the ring spin. "This is pretty cool."

"I know, right?"

"Well, they're getting the hang of each other's powers," Mina observed. "But something tells me that this will not be the only problem they'll face today..."

Meanwhile, Zach arrived with his plane, looking for some animal for his new inventions.

"Bring up the Wild Kratts!" he ordered his computer. "Maybe they're hanging with some creature that I can use."

The monitor brings up the crew currently training. What threw him off were the swapped colors of the brothers.

"What's this? Blue Boy and Green Guy switching it up?... No way, even as kids they always wore those respective colors. Zachbots, see what's going on over there."

The Zachbot peeked from behind a nearby tree.

"So how much time do we still have to find another rainbow?" Chritin asked, though to Zach it was Martin in a green shirt. Mina looked at the hourglass standing nearby.

"About ten hours," she responded. "We've got a lot of time to find a rainbow big enough for you two."

"That's good, 'cause I don't want to be stuck as my little brother forever," Maris said, though it looked like it was Chris in a blue shirt to Zach. That line got the evil inventor even more confused.

"Has Green Guy finally lost it?"

"Yeah, the sooner we cross the rainbow, the sooner things will be back to normal. Being who we are in the right bodies." Chritin said.

"And really Chris, how can you stand the collar so high up?" Maris tugged at the collar before zipping it lower.

"Well, I don't see how this is any more comfortable, Martin." Chritin grabbed his zipper and zipped it up. "Much better." Back at his plane, Zach was realizing their situation and began smiling evilly.

"So it appears the two Rat Brothers have gone through a switcharoo," he mused. "And if they don't cross any yucky, cute rainbows, they'll be like that for the rest of their lives. Oh, this is the perfect way to get revenge for that humiliation in Japan. Zachbot, return to the ship. I got an idea for something that'll... darken the mood." Zach laughed hysterically.

Several hours later, the boys walked around the park to clear up their minds.

"I really hope we find a rainbow soon," Maris said, while he and Chritin walked around the park. Chritin nodded in agreement.

"Look! The Kratt Brothers!" Two girls were approaching them. "Guys, can you give us your autograph?" They were saying.

"Uh-oh," Chritin whispered. "We're in trouble. They'll suspect us when we sign the pictures. I'm left-handed and you're right-handed."

"Don't worry. I have a plan." Maris winked. He whistled the Wild Kratts theme song and Bite-Size came. He heard Maris's plan and flied on the girls' direction.

"Hi, girls! Long time no see!"

"Hi, Bite-Size!" The girls recognized Bite-Size from the time he became human and helped them. While they petted and talked with the little brown bat, Maris and Chritin acted fast and signed the girls' pictures, gave the signatures to them and received lots of fangirl squeals.

"Phew. That was close," Chritin sighed, after the girls were gone. "Thanks, Bite-Size."

"No problemo." The brown bat saluted with his wing.

With that, he flew back to the Tortuga. Suddenly, they heard something rustling in nearby bushes. When they looked, they saw their beaver pal Sticker looking around for something. Maris was about to say hi, but for some reason, Chritin was the one that went to the beaver.

"Hey Sticker," he greeted him. "Lodge still sturdy?" The swapped older brother only stared. His little brother was acting like... him. Like he WAS him.

Sticker didn't seem to notice anything different. He just looked at them and returned to work.

Suddenly, Chritin noticed something different on a tree nearby. It was...gray?

Then it flashed red. Chritin gasped before grabbing Sticker and pulling him away before a robotic arm could grab him.

"Zachbot!" he exclaimed. The Zachbot then retreated into the thicket. "Zach's back." Putting Sticker down, he attempted to run after the robot, but Maris caught his collar.

"Woah! Where are you going?"

"To find out where Zach is hiding!"

"Without a plan?" Chritin turned to his brother, surprised by what he said.

"Since when do you think about having a plan?"

"Since when do you dash off after a Zachbot the first chance you get?"

"I always think."

"And I always just go in." Realization hit them like a freight train, making their eyes widen in shock.

"Oh no," they both said.

The Kratts then made a mad dash back to the Tortuga. "LUNA!" the two screamed. The owl looked their way.

"What's the matter, brothers?" she asked them.

"We have a problem!" She noticed the worry in their expressions.

"Well, two problems actually," Maris said. "The first is that Zach is here and was spying on us earlier."

"Not again," Aviva commented.

"But that's not the worst," Chritin added. "I don't know why, but I think we're..." He gripped his head. "Becoming each other."

"'Becoming each other'?" Jimmy questioned. "As in Chris is becoming Martin and vice versa?" They both nodded.

"Oh dear," Luna said worriedly. "Iris was afraid of this. This happened to previous pairs of people who crossed the rainbow. Their real selves start slipping away from their current bodies and the seemingly original personality the body replaces it. And with every few grains of sand that falls down the hourglass, your true selves are disappearing. If we don't get you two in your right bodies, not only will you remain in them forever, but..."

"We'll also lose the real Chris and Martin permanently?" Mina asked.

"I'm afraid so."

"Our real selves?" Chritin started to panic.

"Gone forever?" Maris followed.

Chritin started crying and flooded the Tortuga. "I don't wanna be like this forever! Not that it isn't good, but I like being me!"

"Hey, stop! You're flooding the HQ!" Maris complained.

The swapped little brother managed to lower it to a few sniffles. Tears still ran down a little.

"Sorry. It really is getting harder to control my emotions. I just can't seem to get a grip on myself." Maris put a comforting hand on his shoulder.

"Hey, no matter what happens, we're still going to be brothers. No rainbow can change that. And I'll be right by you, thick and thin." Chritin smiled at him.

"Thanks bro."

Chritin's sprigs started to move. "Uh-oh... my, I mean, your sprigs are moving!"

"That one means a storm is coming. But that can't be right. There wasn't a single cloud in the sky." Maris suddenly felt pain in his head, making him grip it. In his mind, he saw Zach laughing like a maniac as there was a flash of lightning. Then it showed the sun setting with the brothers still in each other's bodies. When the vision ended, Maris started breathing in deep. Chritin had his hands on his shoulders.

"Martin, you okay?"

"No. I just saw Zach with the storm. And the sun going down. With us still in the wrong bodies."

"Oh no! We gotta hurry, and stop him! Whatever he's doing, it can't be good!"

Zach was joyfully stealing colors from the park with his new invention, leaving it gray, black and white.

Zach evilly laughed. "This park looks a lot better without all those obnoxious colors. Not to mention the Rat Brothers won't be able to switch back afterwards."

"Zach, stop!" Chritin shouted. The rest of the Wild Kratts were right behind him. "What are you doing stealing all the park's color?"

"I'm making sure you two Rat Brothers never return to normal." Both brothers' eyes widened.

"How did you...?" Maris stammered.

"I knew immediately from the shirts. Can't believe those ignorant girls didn't notice the difference." Bite-Size glared at him.

"Hey! No one calls them ignorant!" the brown bat snapped.

"Just return the color to the park, Zach!" Chritin commanded.

"Nah, I think I'll hold onto them. So I can destroy them!" Varmitech flew out of reach. "And now for stage two! Activate the storm machine!" From inside Zach's plane, a Zachbot pressed a red button, which released a ginormous storm cloud. It completely blocked the sun and it began to flash with lightning, followed by thunder. "No light, no icky rainbows." He laughed with vice again as there was another lightning bolt. Maris recognized this scene, making him gasp.

"This is the same as in the vision," he murmured.

"Oh no! We only have thirty minutes till the sun sets!" Chritin started to panic. "We'll never clear it in time!"

"Oh, yeah? Let's see how this storm machine leads with me!" Aviva touched her medallion and started making a wind to send the clouds away. It was tougher than it looked.

"If there's one thing I learned about nature that I will never forget... is that nature is above technology!" With all her might, she made a powerful burst of wind that broke through the cloud. The storm machine started malfunctioning. Unfortunately for Zach, his hover device was rocked by the wave of when it exploded, making him drop the device all the to the ground. Maris caught it with a vine.

"Ow! My eyes!" The evil inventor screamed at the sudden exposure to the light. As he retreated, he shouted, "I'll get you Wild Rats!"

"That's Wild Kratts!" Everyone yelled.

"Awesome job Aviva!" Chritin complimented the good inventor.

"You sure showed Zach!" Maris added.

"Thanks guys," she said to them before retrieving the color stealing invention. "Now let there be color!" The moment she opened the storage cockpit, an explosion of color shot out. As everything returned to normal, the team cheered. That's when Maris realized the sun.

"Oh no, the sun!" he cried out. Everyone looked to see the sun going down.

"Only one minute left!" Mina said, holding the hourglass.

"Prism to the rescue!" Luna flew in the sun's direction, holding a prism she borrowed from Iris. A refracted rainbow appeared.

"We got one shot, bro! Let's hope we make it!" Chritin said and the bros held each other's hands, passing through it in the nick of time.

Both tumbled to the ground when they felt a head rush. They still were hand-in-hand. The sun disappeared in the horizon just as the last grain of sand fell to the bottom of the hourglass. Chris(?) opened an eye, revealing hazel and not blue. His shirt was also back to being green.

"Did we make it? Did it work?" he asked. The crew smiled down at them. Martin's blue eyes shot open at the sound of Chris's voice not coming him. His shirt had also become blue again. The brothers sat up and looked at each other. Both were happy at what they saw.

"Martin?"

"Chris?"

"We made it!" they both exclaimed, embracing each other. The rest of the team joined in.

"And just in time!" Luna pointed out. She used her talons to grab the hourglass. "I think I'll return this hourglass to Iris, too. Bite-Size, do you think you can carry the prism for me?"

"Sure I can!" the little flying mammal said and picked up the prism of glass with his feet.

"Oh, and Mina!"

"Yeah?" Mina said, coming over to her.

"Iris wanted me to give these to the brothers." Using her beak, she pulled out a string with two hourglasses about the size of a cherry with no stem. One was yellow and the other was blue. Both had matching sand in them. The remainder of the team came over. "These hourglasses are filled with a special sand. Both can show events of the past."

"Show past events?" Chris asked.

"Yes. The yellow shows events that took place in the daytime and the blue one for night. Both will run for a few minutes before all the sand is on the other side and can only be used twice a day. You can even give it dates in the past if you want to be specific." Martin received the two hourglasses and handed the yellow one to Chris.

"Tell Iris 'thank you' for us please," he requested.

"I'll make sure to tell her." Luna started taking flight.

"And I won't take long here! This thing's heavy," Bite-Size added. A portal opened for them. "See ya later!" With that, both animals flew through.

"You know, despite all the problems, it was kind of fun being you," Chris commented, patting his brother on the shoulder.

"I don't think 'crying a flash flood' was fun for you," Martin said with a smirk.

"And I suppose getting a headache from just thinking alone is?"

"Hey! You know me!"

"Of course I know you! Because I was you!" The team laughed as the stars started becoming visible.