After receiving a kiss and copping a sneaky feel, Naruto felt as though he were on top of the world. His body thrummed with electric energy, making him feel as though nothing were impossible!
"So, what's the plan, Sakura-chan?" Naruto asked excitedly. "What do we do now, ya know?"
Sakura quickly explained what she had just witnessed. Rather than passing on the torch to her son Menma, Kushina had remained the Nine-Tails' Jinchūriki, since in this world, she hadn't died. And for some reason, the masked man who had sent them to this world had just possessed Naruto's fake mother…
"So, that's the Obito's plan," Sakura said thoughtfully, the pieces of the puzzle falling into place in the middle of her explanation. "He's trying to draw out your Nine-Tails through the chakra resonance phenomenon!"
"Chakra resonance phenomenon?" Naruto echoed.
"What, you don't remember?" Sakura said, startled. "Oh, right… this version of you wasn't there at the time."
An individual's chakra possessed a unique signature, a kind of resonant frequency that shinobi trained in sensory ninjutsu could detect. If two people were in tune with one another, such as family members or lovers, they could make their chakras resonate together and combine their powers in a way that amounted to far more than the simple sum of their strengths!
To better visualise this concept, one might imagine two identical tuning forks set some distance apart. If one were struck, it would produce a note of a certain pitch, and through sympathetic resonance, the other would begin to sing as well.
This was the so-called collaboration ninjutsu; for instance, Naruto's and Sakura's Collaboration Art— Ōoku: Descent of a Palace of Concubines could only function because their wavelengths, for the purposes of this jutsu, were equally perverted and attention-seeking! If Sakura tried to use this genjutsu with Sasuke, who was infinitely better at genjutsu than Naruto, it would fizzle out almost instantly, even if he acted out his part perfectly!
"If possible, you should avoid drawing on the Nine-Tails' chakra to fight the masked man," Sakura said thoughtfully. "Hmm… but even if we both go into Sage Mode, it'll still be a challenge to defeat something as powerful as the Nine-Tailed Fox…"
And then it struck her.
"Where's Menma?" Sakura asked quickly. "He's basically you, so it should be easy for you two to create a cooperation Rasengan! A jutsu that strong should put a dent in the Black Nine-Tails!"
Naruto made a face.
"Don't wanna," he said, wrinkling his nose. "That bastard put his grubby mitts on your butt, Sakura-chan."
"Bring him out anyway," Sakura insisted.
Reluctantly, Naruto released his jutsu, and the Shadow Clones that had been dogpiling Menma and his own clones vanished in puffs of white smoke. Sakura and Naruto looked down at him; the once handsome lad now lay shivering uncontrollably upon the ground, his entire body mottled with black and blue bruises, one of his arms bent at an odd angle behind his back. He was in no state to synchronise his chakra with anyone.
"You got him pretty good," Sakura said glumly, nudging him with her foot. "I suppose we'll have to apply domestic violence to your mum the old-fashioned way."
Things were not looking good. How was she supposed to juggle defeating Obito, who was possessing Kushina's body, and keeping Naruto's mental state above the threshold at which the Nine-Tails could not influence him, all the while wailing on a woman who looked very much like his mum?
"We could always try the Cooperation Rasengan with the two of us, ya know?" Naruto proposed eagerly. "We can do it! I believe in us, believe it!"
Sakura doubted they would be capable of pulling off such a jutsu without practising it first.
Back during the Lōran affair, the only reason Minato had managed to form a Father–Son Rasengan was because Sacred Timeline Naruto had been exhausted and he himself was a prodigious genius, allowing him to attune his chakra perfectly to his son's manageable supply of chakra. And the only reason Sacred Timeline Naruto and Darkest Timeline Naruto had been able to bring their chakras into harmony was because they were, in essence, the same person.
"I suppose it can't hurt to try," Sakura said tentatively. "Hold out your hand, Naruto."
The air above Naruto's hand shimmered as he expelled vast amounts of chakra into the atmosphere from his palm's Tenketsu, and Sakura quickly got to work kneading her own chakra into it, moulding their combined chakras into a sphere, and…
BOOM!
The Rasengan exploded in their faces.
"That was close!" Sakura gasped, as she fell over onto her fat butt. "I almost lost my fingers there!"
Naruto's chakra was too strong, and there was simply too much of it, while Sakura's was too weak. With practice, Naruto would be able to modulate his output to match the weakest link, but that could take months, perhaps even years of marriage, to get right.
After all, they were not blood-related. Thankfully.
"We have to try again," Naruto said with determination. "This time, for sure… guh!"
Without warning, Naruto's knees flagged, and he wavered. Groaning, he clapped a hand to his forehead as if to ward off a headache, and when he removed his hand… Sakura saw that his pupils had turned into vertical slits.
"Naruto, what's wrong?" Sakura said worriedly.
"Voices… in my head…!" Naruto growled. "I can't… shut them out… ya know!"
Sakura's eyes widened in comprehension.
The Black Nine-Tails was rampaging across the newly rebuilt village, destroying the blood, sweat and tears people had put into rebuilding their homes, stampeding and crushing people underfoot… it was generating enormous amounts of negative emotions. The Nine-Tailed Fox had the power to detect these emotions, which was why it liked to call itself the embodiment of hatred…
Obito was forcefully making Naruto's Nine-Tails resonate with Kushina's from his own end!
They didn't have the luxury to sit around and leisurely discuss plans; not while the villagers of this world were locked in a life-or-death struggle against Obito and the Black Nine-Tails flattening their village! If Sakura didn't stop this conflict soon, Naruto would be overwhelmed by the villagers' emotions!
"Don't go into Sage Mode, it'll only make the voices louder," Sakura said warningly. "Stay right here and try to ignore them. I'll try to figure something out!"
With a running jump, Sakura started leaping across the village towards the Black Nine-Tails, whom Minato was luring away using short, consecutive jumps through the Flying Thunder God Jutsu. Sakura zoomed in on them using her Byakugan. It looked as though the Akatsuki were helping him and the village's elites?
"I'm coming with you, ya know!"
Sakura glanced over her shoulder as she soared through the air. As expected, Naruto was not going to sit around twiddling his thumbs while she headed towards danger on her own!