A/N This chapter has a T rating.

It seemed like any other day, really. And that was its own paradox.

Kwazii ruffled the top of Peso's head as he passed. "Ready to come toe-to-toe with some monsters?"

Shellington laughed, "There's no such thing!"

"Yeah," Peso chimed in, then gulped. "...Right?"

"Actually, according to the scientific community..." the Professor began.

"Not you too!" Shellington exclaimed.

"Let me finish," the Professor said graciously. "'There is no such thing as 'monster.' There is only species,' the late raccoon scientist Brakoff had once said. In a way, that is true. There are some such monsters that have been portrayed in folklore that are actually, undoubtedly, real."

"Really?"

"See, I told you!"

"Take the kraken, for example. This mythological creature was said to be a large, tentacled monster that sunk ships. In actuality, it is a species of cephalopod called the colossal squid. It is basically a member of my family."

"Huh," Shellington put a paw to his mouth, deep in thought, "I never thought of it that way..."

Kwazii did a cashier motion.

"...But just because some 'monsters' had turned out to be real-life species," Shellington said, "that does not mean all of them are real."

Kwazii pouted, or what Peso considered his version of pouting. He "arghed," slumping his shoulders and tail.

"Chimeras, hydras... They can't possibly exist."

"I don't know about any of them monsters," Kwazii butted in. "But I do know some of them had to be real. Why, there's some pirates that I know that had actually encountered some, like the kelp-looking Dabbalock."

"And who, exactly, saw them?"

Kwazii faltered, stuttered. "It doesn't really matter. You don't know him anyway."

Shellington nodded, trying to hide his smirk, "Uh-huh."

"But it was real, I tell ya!" Kwazii said enthusiastically. "Just you wait, me hearties. We'll see a real monster one day. That's going to be a real adventure!"

"I-I think..." Peso said, shifting from one webbed foot to another, "...we have quite the adventures now. We're seeing the sights, helping others, traveling the world... I'm glad I'm here."

There was a pause, as everyone thought it over. Peso hoped they didn't take some sort of offense to it, or thought it was weird.

"Well, you're right on that end," Kwazii said, clapping Peso on the back. Peso got a little unbalanced at the motion, but straightened up.

Captain Barnacles arrived in the Launch Bay. Everyone looked at him expectantly.

"All right, everyone," he said as he came in front of the large computer monitor. "Thank you all for waiting. As you all know, today will be a typical research and medical mission. Peso will do checkups on the locals, Dashi will take photos, and Shellington will conduct research. Kwazii and I will help in whatever capacity we can. Who's with me!"

"Yeah! " they all cheered.

"Good," the Captain nodded, pleased with the results. "Good. Octonauts, let's do this."

It did not take long to get knee-deep into the mission.

Peso tied a knot on the bandage of a sea slug, giving a final pat before sending it on its merry way.

He could see Shellington several yards away, having a microphone and other equipment about him. He seemed to be asking questions to some fish nearby.

On the other side of Peso, Dashi took a few pictures of the reefs around her. Then- Peso thought it was curious- then Dashi went over to Shellington and seemed to help him on his inquiry, holding the microphone for him as he fiddled the controls.

Huh, Peso thought. Dashi's helping out in the science stuff now? Must be a new thing. Then Peso shrugged internally. If no one said anything to him, then he shouldn't pry. He couldn't be rude, now.

He went back to work, about to greet the next patient in line, when all of a sudden he heard screams. It was a flurry of them, rising in intensity.

And he could hear Shellington and Dashi among them.

Peso's heart quickened as he looked at the source of the noise. The group of creatures had scattered. He saw blood.

"Octonauts. There has been an attack," Captain Barnacles' voice came staticky on his intercom. "Shark."

At that one word, Peso's mind seemed to freeze; but his body went into action. Using his penguin flippers, he swam as fast as he could, slipping past the creatures that were zipping each way in their chaos.

Where's the shark? Where's the shark?

He had to get to a safe place. Somewhere among the coral.

"Help!"

The voice was raw, fear-stricken. It paused Peso in his tracks, his gaze trying to find the source of it.

There.

A white marlin was drifting, sideways, in the water. He was large, about five feet long, and his snout was similar to a swordfish's. Blood was oozing from his side.

Wasting no time, Peso came up to the marlin. He grabbed him and pulled the heavy fish along with him to the coral. Once behind a large mound of coral, Peso turned to him.

The marlin's side has been ripped open. His gills were working overtime.

"Help me, I can't breathe, I can't breathe-"

"Calm down," Peso said as gently as he could, softly putting his flippers on the marlin's head, trying to figure out what to do. His own flippers were shaking.

A part of his side is gone. Major bleeding. Portion of stomach and intestines missing, making bile and digested food able to escape. They are contaminating the other portions of the body.

Peso's heart sank.

I need to perform surgery. I don't have the proper equipment for this!

"Octonauts," Peso said to the radio. "I have a marlin that needs intensive care. I need to bring him to the Octopod. Is it safe?"

Peso looked above the coral and immediately ducked his head down. In that one moment, he could see a gray blob swimming quickly, which must have been the shark.

"We'll come as fast as we can," the Captain said. "Kwazii, you distract the shark, Shellington, you-"

Peso tuned them out, needing to focus on the patient before him.

Peso couldn't take the marlin now. Even if he did, he would need help to transport him to the Medical Bay. This marlin was as big as Peso was, and two times heavier. Out of the water, there was no way the medic could carry him alone.

"The shark- the shark it-!"

"Sir, breathe in with me." Peso needed him to calm down, or else he might hyperventilate. The penguin breathed in and out slowly, trying to make the marlin do the same. It took a couple tries, but he eventually followed the doctor.

All the while, Peso put pressure on the wound with one flipper, using the coral reef to hold the marlin in place. With his other flipper, he opened his medical bag. Even if he didn't have the proper tools, he had to do something.

The stomach contents are spilling. That needs to be taken care of first.

Peso took out a syringe and used it on the marlin. It would help with the pain a bit. Especially with what Peso had to do next.

"Octonauts, two other sharks have arrived. I repeat, two other sharks have arrived."

Peso's breath quickened, but he controlled it again for his patient's sake. He was hidden; he had to focus on the marlin.

Peso took out a cloth and, removing the pressure on the wound, used it to try to clean as much of the stomach filth as he could. If it stayed in there, it would cause infection.

He was glad he couldn't smell it with his helmet on.

Not all of it was gone- a little bit was sticking to the other organs-but he got most of it out. Hopefully that was good enough for now.

Peso took out a packet of blood clotter. He could use it to stop the wound from bleeding until he could properly stitch up the organs and flesh later.

Stupid! That can't work! What, you have pieces of marlin stomach lying around? Half of it is missing. It's too late for him.

He knew that. Peso wasn't stupid, he knew exactly that. But, maybe, something could still be done. "I have to try," he muttered.

He activated the blood clotter, and it started to harden over the wound.

The marlin was breathing shakily. "Ah-that hurts!" He tensed up. "What's happening?" His voice became slurred.

"It's okay," Peso tried to soothe. "This will help with the bleeding. As soon as possible, I'll get you back to the Octopod and fix you."

The marlin didn't seem to listen. He tensed up again, and his gills slowed. Peso's eye's widened, and checked his pulse. It was low.

He was going into shock.

"No no no," Peso tried to do chest compressions as best as he could, with half of the marlin's side gone.

"Stay awake. Can you hear me?"

He didn't respond.

"Octonauts, I need backup!." Peso said into the collar radio. He tried to stay calm, but it wasn't working.

He continued the compressions.

"I got your coordinates." Dashi's voice, thank goodness she was alive. "We're coming."

He should have been glad, he should have, but the marlin wasn't responding to the compressions and his gills have stopped and he can't feel a heartbeat anymore and he had to keep trying and he had to keep going and-

A white paw landed on his shoulder.

Peso painfully slowed.

He was dead.