Disclaimer: Naruto is the property of Masashi Kishimoto, who created the Naruto cast. None of the characters are my own (except the dog).

Author's Note: Thank you, Eland Vary, for the information and Anilon for your review!

They had been tracking the rogue ninja for three days through the trees and along the river, but when they came to the marshland on the border of the Land of Fire there was not a trace of him to be seen.

"Not a single step further, Naruto," said Kakashi, throwing out his hand as the boy prepared to spring forward into the mist.

"But Kakashi-sensei! He's out there. We can still catch him – "

"If you know the way through the marshes, then by all means," Kakashi's eye crinkled at the corners in a smile. "But, I've heard that the swamps out there are bottomless, that the friendlier ones spit fire and that the carnivorous plants are exceptionally hungry, especially for stupid, hot-blooded, reckless Konoha ninjas."

Naruto stopped struggling against Kakashi's hand. He straightened to scratch the back of his head. "Maybe not today then," Naruto said. He glared out over the misty marshland as though it had done him a personal insult, simply by existing. "Still bites though, that he got away."

"At least we've managed to learn how the rogue ninjas from the Land of Mud have been getting into the country," Sakura said, although she looked just as glum as Naruto. "We can call that a plus."

"Until we've mapped a safe route through, there's not much we can do." Kakashi put his hands on his hips and the three of them turned back to the wide expanse of mist and purple moss stretching far, far into the distance until the horizon was lost in a bank of cloud.

Naruto sighed and muttered something under his breath. Kakashi smiled again. "Cheer up, Naruto. With their route through the marsh, the Mud ninja think they can come and go as they please. We'll be seeing them again soon."

Naruto nodded and looked a little happier. "And when we do, we'll kick their butts!"

They decided to send a message to Konoha for a mapping and surveying team. Until the team arrived, they would have to keep watch. Once they had hastily set up camp in the branches of a huge black pine that stood at the edge of the marsh like a watchtower, they sat down around a lantern and wrapped their cloaks about them.

"Here you go, Naruto, Sakura," said Kakashi, holding out their field rations.

Breaking the seals on the packets, for a moment there was a quiet of biting, chewing and grimacing, until Naruto gasped and gagged for air. "Why can't they make them taste like miso or something instead of sawdust?"

"It says on the packet that these are Field Rations Version 3.2," Sakura read off the foil in her hand. "They should taste better than the 3.1 rations we had last time we went on a long trip."

"Not quite, Sakura-chan." Kakashi adjusted the front of his mask and dusted the crumbs from his jacket. "It means that they're supposed to give you more stamina than the rations we had last time. If you want something with more flavour, I hear that frog tastes like chicken, and there is a marsh just – "

"When did we last go on a long trip again?" Naruto asked, chewing slowly on the ration bar with watering eyes.

Sakura looked at him and lowered her ration bar.

Naruto slowed his chewing. He glanced down at his feet. "Oh. Oh yeah. That's right. Looking for Sasuke."

The brief silence that followed wasn't awkward, but simply, just for a moment, sadly aware that there was one empty space around the lantern. Kakashi rolled his eyes up towards the black branches above them, counting down until the best moment for him to step in and clear his throat, but Naruto suddenly said, "Wonder what that bastard's up to now."

"Making a name for himself no doubt," Kakashi quipped, trying to lighten the tone. He flicked up a finger. "Ah yes, I thought I'd show you something amusing! Just a moment."

He turned to his pack and began rummaging inside. When he pulled out a book, Naruto instinctively shrank away. Sakura squeaked and covered her eyes.

"No, it's not what you think it is," Kakashi deadpanned, sighing and waving the book in front of Naruto's face to prove his point. "It's the latest edition of the Bingo Book, and there's a new page for our old friend – "

"What?" cried Naruto. "Give me that book!"

"You can look it in a moment. Now let your sensei have his fun first. A couple of us jounin realised something the other day when we were looking through..."

Naruto and Sakura watched in bemusement as Kakashi flipped through the pages until he came to a page that was dense with writing and had a grainy photograph of a stern-looking face on it. He held up the book: "This is Itachi."

"We know, Sensei." Sakura squinted at the picture critically. "The quality of the photos in the Bingo Book hasn't got any better, has it?"

"Sakura, the photographer of the Bingo Book was using a scoping jutsu from three hundred metres away and he still nearly died getting this photo," said Kakashi sternly, narrowing his eyes. "You should show some more appreciation. Anyway," he turned one page, "in alphabetical order, the next one is – "

"Sasuke!" Naruto exclaimed, leaning forward eagerly.

"Now keep looking at Sasuke – " Kakashi let the page slowly flip over before looking up at Naruto and Sakura, clearly beaming beneath the mask. "Haha! See?"

Sakura raised an eyebrow. "What are you doing, Sensei?"

"That's Itachi," Naruto said blandly. "You're just covering his tear troughs with your thumbs."

"I know that. But look!" Kakashi lifted his thumbs and turned the page to Sasuke, then flicked forward again to Itachi's photo and planted his fingers on the man's curiously prominent facial lines. "They look exactly the same!"

"Is that," began Sakura, sounding about as unimpressed as Tsunade finding all the 'hospital use' ice cream missing from the store room, "a jounin's idea of a joke?"

"I thought a jounin's idea of a joke was Gai-sensei," Naruto remarked.

Kakashi regarded the two of them with a deep disappointment. "I was wrong. You two are still much too young to understand the adult sense of humour."

Before Naruto could untangle the cloak from his shoulders and leap to his feet, there was a soft noise like tearing fabric, a plume of smoke, and a bandy-legged bulldog with a Konoha forehead protector appeared on the branch beside them. Its eyes were rheumy and red. The folds of flesh around its face and jaw wobbled and its crumpled-looking head was the shape of a battered football in desperate need of pumping.

"Yo, Master Kakashi," it said, lisping through its underbite and drooling. "I got your message to Tsunade. She's just sent out a squad of six. The surveying ninja are travelling light and, from what I saw, they travel fast, so they'll be with you the day after next."

"Good work, Purupuru." Kakashi tossed the dog a biscuit, which Purupuru snapped out of the air.

Suddenly Kakashi froze. He watched the bulldog crunching the biscuit between its teeth and then slowly looked down at the Bingo Book in his hand. From Sasuke's page, he turned it over to Itachi's, and stared.

"These lines on Itachi's face," he started quietly, putting a thumb and a finger to his chin. "Who told you they were tear troughs, Naruto?"

"Sakura-chan, and I know she's right, because she's a medic and she knows all about genetics and weird biology and stuff," Naruto replied, grinning toothily at Sakura as though he had paid her a wonderful compliment.

Sakura shrugged. "It was either that or nasolabial folds, and I don't think Itachi laughs enough to qualify for those."

"Well I've had a better idea," said Kakashi with a nod. He turned to Purupuru the bulldog. "Purupuru, could you come here for a moment?"

Purupuru swallowed the biscuit and edged somewhat reluctantly along the branch towards them. When he was within arm's reach, Kakashi seized him by the scruff of the neck, picked him up and dropped Purupuru in front of him. Folds of flesh expanded and collapsed like an accordion. Purupuru sighed as though he was used to being manhandled all the time.

"How much do either of you know about dog breeding?"

Sakura and Naruto exchanged a nervous glance.

"I see. Well, here's a crash course then in the miracle of selective breeding," Kakashi continued, ignoring Sakura's blushing. He put his hands around Purupuru's face. "Bulldogs were bred for fighting. Some people might say they're plug ugly and look like shrunken heads – apologies for any offence, Purupuru – "

"None taken. Reality is cruel," Purupuru said, although his voice was somewhat muffled by Kakashi's hands.

"- but every inch of the bulldog has been designed for success in bullbaiting. They've got a low centre of gravity to stand their ground, wide mouth with a strong jaw for a firm bite, and these folds and lines on its face," Kakashi looked up at Naruto and Sakura to make sure they were paying attention, "have been bred into the bulldog to act as channels for blood. Uchiha Fugaku also had these lines on his face, so potentially there's a genetic basis to them."

"My head's hurting," muttered Naruto.

"Now, what else in the Uchiha clan has a genetic basis?" Kakashi went on, playing with the folds on Purupuru's face. "Sakura? Any guesses?"

"The Sharingan, sensei?" Sakura answered reluctantly.

"The Sharingan. Precisely," said Kakashi with a teacherly nod of approval. "And overusing the Mangekyo Sharingan can make your eyes weep blood. These lines on Itachi's face are Uchiha genetic blood channels to drain blood out of the way of their mouth."

Sakura blinked slowly, the corners of her lips twitching. "Like Purupuru's?"

Kakashi nodded and patted Purupuru's head. "Just like Purupuru's blood drainage folds here."

Sakura slapped her palm to her forehead. Naruto gaped, glanced down at the bulldog, who was rolling its eyes, before saying, "Nope. I don't buy it. Sakura-chan says they're tear troughs, so I'm going to say they're tear troughs too."

Kakashi let Purupuru's face go and the dog slumped forward to rest its chin on its paws. The corner of Kakashi's eye turned up again in a smile. "Naruto, do you even know what tear troughs are?"

Naruto's mouth opened and closed and a blank expression flickered across his face. "It's from…you know, because he's deep down probably really depressed and all…Itachi crying a lot?"

Kakashi arched an eyebrow at Sakura, who folded her arms and pursed her lips. "I already tried explaining once, sensei, but I couldn't keep his attention long enough for him to listen."

"Itachi doesn't cry?" Naruto seemed sceptical. He shook his head in fierce denial. "But Sasuke cries loads!"

"Naruto, you've never seen Sasuke cry," Sakura argued. "You're just saying that because, for some reason, you still think of him as your rival and you can't justify crying lots unless he does. I mean, Naruto, you really could do with some drainage channels on your face. You cry more than I do."

"Ouch. Burn." Naruto and Sakura glared at Kakashi, who held up his hand and smiled innocently. "I accidentally touched the lid of the lantern."

Naruto turned back to Sakura with a mischievous grin. "I bet Sasuke does cry. Bet he poses with it too. He'll find a nice rock on a shore, or a cliff, and when the sun's setting, and the atmosphere's totally perfect, he'll cry into the sunset, then when he's done, he'll turn around, the wind blowing his hair, and he'll say something cool like, 'It's just the salt wind in my eyes' -"

Sakura raised her fist and Naruto's voice rose an octave higher as he squeaked, "- But don't worry, I'm sure they're very, very manly tears - "

"Naruto – "

As Naruto let Sakura punch him, Purupuru made a low rumbling noise in his throat. Kakashi started. He patted his pockets. "Sorry. I should probably give you another biscuit for that - "

"Don't need one." Purupuru looked up at Kakashi from under his sagging eyebrows. "That's a good team you've got there. It's nice to see you having a laugh for once."

Kakashi hesitated and looked across the lantern at the two young ninjas opposite. They had moved on to a very verbal argument indeed. Kakashi had a feeling that Naruto would win, because he was too stubborn to lose. He was reliable in that way, but they couldn't underestimate Sakura. She was becoming quite well versed in Arguing-no-Jutsu Tsunade-style.

He looked down at the Bingo Book and turned to Sasuke's page. There wasn't much writing yet. Kakashi was amused to note that Sasuke's eyes were turned towards the scope. He had noticed the Bingo Book photographer even from three hundred metres away.

Kakashi closed the book and tucked it into his bag.

"They've got a bit more to go yet," he said to Purupuru, before raising his voice. "Alright, alright, calm down now. We're supposed to be on watch for rogue Mud ninja remember?"

"You can talk!"

Purupuru closed his eyes and vanished in a puff of smoke, unnoticed.

Final part, we'll hear something from Itachi. Hope you enjoyed this chapter!