The plot of Naruto Shippuden: The Lost Tower wasn't complex.
The novelty was the special Dragon Vein.
According to official lore:
The Dragon Vein is the earth's lifeline, with chakra far surpassing other places. Mishandling it could destroy the land.
That sounded very much like a world will.
As for time travel, it likely related to the Flying Thunder God Technique.
Flying Thunder God is an S-rank space-time ninjutsu.
With absurdly high energy, time travel would be within reach.
The question was whether it sent you to the past or into a parallel world.
In the movie, it seemed like the former.
Because the chakra blade Naruto accidentally left became Sara's relic.
If it were a different parallel world, that'd be hard to explain.
There was another peculiarity.
Though Mukade and Naruto's group triggered the seal together, they arrived at different times.
Mukade arrived earlier.
This showed the Dragon Vein's instability.
Natsume wasn't sure if Danzō, triggering the Dragon Vein now, would go back twenty years.
If he did, what if he changed the past wantonly?
At the end of the movie, Minato erased everyone's memories to prevent historical disorder.
He didn't even recognize Naruto.
Clearly an implication.
There might be a "world will" that corrected things.
Either way, Natsume couldn't let Danzō go alone.
At the very least, he had to go with him.
No—best if he went alone to take a look.
Maybe he could farm some Fate Points.
As for coming back, if Flying Thunder God didn't work, he'd rely on the Ring of Fate.
Better that than letting Danzō run amok.
"Lord Natsume."
Kurenai Yuhi knocked and entered, walked to the desk, bent slightly, and handed over a file. "This is what you asked for."
"Thanks."
Natsume glanced over it and thought, nice.
Kurenai wore a white blouse, with the top button undone, exposing a pale neck.
Below was still a black pencil skirt, but the usual black stockings had become white.
Both had their charms, though that wasn't the point.
By rights, Kurenai wasn't the type to change outfits.
In the original, she practically wore the same clothes to the end.
The change started when she became the Hokage's secretary.
Ahem.
I'm not that casual.
Natsume opened the file and read.
It recorded the mission when a young Namikaze Minato, Aburame Shibi, and Akimichi Chōza went to Rōran.
But it was very brief.
Their memories had been self-erased.
Still, confirming Rōran's location from the mission record was enough.
"Kurenai, please return the file."
After memorizing the location, Natsume handed it back.
She nodded, swayed her hips, and left.
Flying Thunder God.
Natsume appeared in the Land of Wind.
He'd previously sent shadow clones all over the world to leave Flying Thunder God markers.
This one was closest to Rōran.
He narrowed his eyes.
Desolation in all directions—just yellow sand.
A vast desert.
In terms of environment, the Land of Wind and Sunagakure had it worst, so they were the poorest.
As Kazekage, Rasa had to use Magnet Release to pan for gold to make ends meet.
Truly tragic.
Harsh conditions forced Sunagakure down an elite path, prioritizing prodigies.
Why could Gaara become Kazekage at fifteen?
This was part of the reason.
If you're strong enough, that's enough.
Natsume clapped his hands and entered Sage Mode; his senses expanded in an instant.
Rōran's legend had long been known, along with "ruins."
Sunagakure would've investigated.
But Minato's seal couldn't be unraveled, so they had to leave it.
The Dragon Vein seal used Flying Thunder God plus Uzumaki sealing.
Sunagakure naturally had no way—until Danzō arrived.
In other words, there should be many shinobi at the site now.
With his senses spread, Natsume found something.
He sped toward the depths of the desert.
The sandstorm grew fiercer, shrouding heaven and earth; visibility under a meter.
For Natsume, this only made cover easier.
He finally arrived at a ruin.
Though half-collapsed, you could still make out the shape of a great city.
Natsume rubbed his chin.
That meant Naruto would still time-travel soon and defeat Mukade—Anrokuzan.
Otherwise, what remained wouldn't be ruins but a bustling puppet city.
As expected, many Sand shinobi patrolled the perimeter.
Natsume opened his Eternal Mangekyō and slipped inside.
Near the center of the ruins, he found a familiar face.
Baki.
A Sunagakure elite jōnin.
Teacher of Gaara, Temari, and Kankuro.
His status was akin to Konoha's Legendary Sannin.
Clearly, the entrance was here.
Natsume sensed downward and detected a familiar fluctuation.
Shimura Danzō, and a Flying Thunder God kunai left by Minato.
At the same time, he sensed the terrifying chakra and natural energy of the Dragon Vein.
Vaster than Kurama.
No wonder it could warp time—it was too much.
This world had many mysterious things.
Meteorite of Hoshigakure, the Hero Water of Takigakure, even the Shinigami and Jashin.
Hard to say if they were linked to the Ōtsutsuki.
Thinking of the three great summoning sanctuaries, that could also fit.
There was a native system, after all.
In Natsume's senses, the Dragon Vein seal had been badly damaged.
It wouldn't be long before it was undone.
But what was Danzō planning?
His earlier quip that Danzō wanted to go back to be Hokage clearly didn't hold.
He didn't even know the Dragon Vein could time travel.
More likely he wanted to use it against Natsume.
If so, the unsealing date would likely be set to the day of the Sunagakure–Konoha alliance.
Using the sudden energy surge, it wouldn't be hard to kill some shinobi.
Natsume could seize the chance to show power and fully win over Konoha shinobi.
Of course, that assumed he guessed right.
To verify, Natsume weaved signs and summoned a slug smaller than an ant to sneak in.
Through shared vision, he saw the underground chamber more clearly.
On the central dais stood Minato's special kunai.
All around was a barrier formed of seals.
Natsume couldn't use sealing arts, but he could recognize them.
Uzumaki seals.
After all, Minato's wife was Uzumaki Kushina.
Right now, Danzō was working hard to undo them.
At this rate, he needed a few more days.
Relieved, Natsume returned to Konoha.
But he left the tiny slug and a Flying Thunder God marker.
If anything happened, he could teleport instantly.
…
Hokage office.
Shizune was startled by Natsume's sudden appearance.
Patting her chest, she complained, "Why use Flying Thunder God even inside Konoha?"
"I took a trip to Sunagakure."
Natsume didn't hide it. Sitting down, he asked, "What did you need me for?"
"Konoha Hospital has a surgery tonight, so please head home early and cook for Lady Tsunade."
Shizune blinked.
In truth, that was a lie.
Tsunade had told her not to come home tonight.
Shizune was stunned.
Had it really come to this?
Knowing about Natsume and Tsunade, she should've moved out.
She hadn't.
She wasn't sure what she felt.
"Got it."
Natsume didn't suspect anything and agreed.
"I've delivered the message. I'll head to the hospital."
Shizune glanced at him, shielded Tsunade's secret, and left.
…
Dusk.
Natsume stretched.
Without Tsunade, the work was a lot less fun.
But it was fine—he'd see her soon.
Flying Thunder God.
He appeared at his home's entryway.
"Sis, I'm back."
He changed shoes and called out.
"Welcome home."
Tsunade stood and walked up to him.
He saw the tenderness in her eyes.
With her gentle, beautiful smile, she looked every bit the virtuous wife waiting for her husband's return.
"How's my outfit today?"
Tsunade twirled, expectation on her face.
"Beautiful."
Natsume had noticed her outfit the moment he stepped in.
A fitted kimono wrapped her shapely figure, the collar pulled down to her collarbone, the bright abyss at her chest dazzling.
Below, a high slit revealed voluptuous thighs and feet in white ankle socks.
The kimono was white, dotted with pink sakura.
Dignified yet sexy.
Two contradictions combined so well he couldn't look away.
Natsume recalled the "reward" Tsunade had promised before the daimyō meeting.
Was this it?
"Do you like it?"
Her amber eyes glowed with charm.
"I do!"
He hugged her. "I like you in anything."
"Sweet talker."
Smiling, she asked gently, "How about I cook tonight?"
"…?"
Natsume froze, then hurriedly said, "You're pregnant—let me."
"Do you dislike my cooking?"
She pushed him away, still smiling, but her lips pursed slightly in mock annoyance.
"Not at all!"
He switched tactics instantly. "Then I'll trouble you tonight!"
"Good boy."
She tugged the kimono up a touch and teased, "Guess what's under here?"
Natsume sucked in a breath, staring at her thighs.
After Mikoto's multiple lessons, he knew kimonos didn't need underwear.
Meaning—nothing underneath.
"At this rate, you won't get dinner."
He swallowed.
"Don't want dinner?"
Her smile could steal souls; she licked her lips. "I planned to personally serve you."
Sure she was teasing, Natsume stopped hesitating and scooped her up.
"Let's bathe."
Leaning in his arms, her pale fingers stroked his cheek. "Now comes the test of your patience—kimonos are hard to put on and even harder to take off."
"I'm very considerate."
Natsume grinned with confidence; he was well-versed in kimonos.
Mikoto loved them, after all.
...
In the steamy confines of the bath, Natsume carefully set Tsunade down on the edge of the tub, the warm water already filling the air with a soothing mist. He knelt before her, his hands steady as he began the intricate process of unwrapping her kimono.
The fabric clung to her curves, and he took his time, peeling it away layer by layer, revealing the soft swell of her pregnant belly and the full, inviting swells of her breasts. She watched him with half-lidded eyes, her breath hitching as his fingers brushed against her skin.
"You're taking your time," she murmured, her voice a husky whisper, as he finally slid the kimono off her shoulders, letting it pool around her feet. Naked now, her body glowed in the dim light, every curve accentuated by the steam.
"Patience is a virtue," Natsume replied, his own clothes quickly discarded. He guided her into the warm water, the two of them sinking in together. The bath was spacious, the water lapping gently at their skin as he pulled her close, her back against his chest. His hands roamed softly over her body, starting at her shoulders, massaging away any tension, then trailing down to cup her breasts. They were fuller now, sensitive from the pregnancy, and she arched into his touch with a soft moan.
"Mmm, that's good," Tsunade sighed, tilting her head back to capture his lips in a deep, lingering kiss.
Their tongues danced slowly, the heat of the water mirroring the building warmth between them.
Natsume's fingers teased her nipples, rolling them gently until they hardened under his touch, eliciting gasps from her.
One hand ventured lower, caressing the curve of her belly with reverence, then dipping between her thighs.
He found her slick and ready, his fingers exploring her folds with feather-light strokes, circling her most sensitive spot without rushing.
Tsunade's hips bucked slightly against his hand, her breaths coming in short pants.
"Natsume... more," she pleaded, turning in his arms to face him.
The water sloshed around them as she pressed her body to his, her hands wandering down his chest, tracing the lines of his muscles before wrapping around his hardening length.
She stroked him slowly, her grip firm yet teasing, matching the rhythm of Natsume's mouth trailed down her neck, sucking lightly at her pulse point, while his free hand kneaded her thigh.
Tsunade's moans filled the room, echoing off the tiles, as he brought her closer to the edge with expert precision, his thumb pressing just right against her clit.
Finally, with a mischievous glint in her eyes, Tsunade shifted lower in the water, her lips brushing against his chest, then his abdomen.
"My turn to serve you," she whispered, her voice laced with promise.
She took him into her mouth, her tongue swirling around the tip before she enveloped him fully.
Natsume groaned, his head falling back against the tub's edge, fingers threading through her damp hair as she worked him with skillful, deliberate movements—sucking, licking, and humming softly to send vibrations through him.
The warmth of her mouth contrasted with the bath's heat, driving him wild.
They lingered like that, lost in the intimacy, until the water began to cool.
An hour later, they finished bathing.
Tsunade, soaked too long, lay limp on the bed to rest.
Natsume dried her golden hair.
His fingers grazed her pale back.
She shivered and lifted her head, the flush not yet faded.
"I can use Yin Seal," she murmured.
"What are you saying?"
Natsume glared. "You can't risk the slightest thing right now. Understand?"
Tsunade hesitated, then nodded.
She sighed inwardly. Alone, she really couldn't beat Natsume.
….
A new day.
Natsume went back to work.
With Tsunade pregnant, he didn't let her overwork—no risks.
No choice.
He'd shoulder more himself.
Opening the door, he found someone already in the office.
Hinata.
She sat on the sofa, absorbed in a report.
Hearing footsteps, she looked up, smiled sweetly, and said, "Natsume-oniisan."
"What are you reading?"
Natsume couldn't help asking. "So focused."
"It's our mission report."
Hinata stood and handed it to him. "I wrote it. Please check it."
Natsume remembered that after completing a mission, shinobi submitted a report to the Hokage.
The content was simple: a detailed account of the mission.
Most shinobi didn't care—just a formality.
They'd scribble a rough outline; no one complained.
Hinata's seriousness was rare.
Natsume scanned her elegant handwriting and nodded.
No surprise from a big clan.
Her writing was beautiful and neat.
"I'll take a close look."
He noticed the expectation in her eyes and smiled.
Hinata tilted her head slightly, a hint of unease on her face.
She cared too much about Natsume.
Even small things—she didn't want to let him down.
She used to care most about her father's evaluation; now Hiashi had stepped back.
"Want the truth or a white lie?"
After reading, Natsume felt like teasing her.
"Um… the truth."
Hinata opened her mouth, sensing something ominous, and nervously clenched her hem.
Like a good student waiting for critique.
"Mm… so good I don't know where to start."
Natsume drew out his tone, then delivered the second half under her worried gaze.
"Eh?"
Hinata blinked.
A moment later, she realized he was teasing.
She lowered her head, a lovely blush rising even beneath her eyes.
She didn't dislike it—she was happy.
Natsume patted her head. "Do your best next time."
"Mm."
Hinata answered softly.
"You've all worked hard these days, so I'm giving you some time off."
Natsume needed to handle the Dragon Vein, so he used that reason to dismiss his three students for now.
After Hinata left, Kurenai entered the office again.
"Lord Natsume, news from Sunagakure—they want to formalize an alliance in a week, at a location in the Wind Country desert."