Compared with the countries in the south, the Frost Kingdom is still a little too cold, and the winter is particularly long.

The further north you go, the thicker the snow becomes. While the ice and snow in the south have just begun to melt, the vast white snow scene in the north shows no signs of changing.

In an area with dense water networks, it is not easy to find the source of a stream, especially under the cover of ice and snow, it is even more difficult to find the clues that Shuimu wants.

Sometimes Shuimu even had to go deep into the underground river to obtain some water samples and test which tributaries he was looking for.

"This won't work."

If there is no improvement in the method, this search will be abandoned halfway.

As a last resort, Yongjie had to go back to ask for help.

Half a day later, Nobumasa and Yusuke arrived at the Frost Kingdom again. This time, with the help of the Byakugan, they were able to travel much faster.

"Is this way of searching effective?"

Xinzhen was a little confused. It wasn't a big deal, and it felt like a waste of time to come here with such fanfare.

Yusuke nodded with a serious expression.

"The lake water that can kill aquatic creatures was discovered in Taki Country. The same thing was found in Frost Country thousands of miles away. Although we still cannot analyze what dangerous substances are in the water, it is very likely that there will be some incredible discoveries."

There aren't so many coincidences in the world. There must be some connection between the two, but it just hasn't been found yet.

The poisonous water from the Frost Country flowed downstream, causing a long winding river to be lifeless, indirectly affecting the Taki Country thousands of miles away.

This is no small matter. You know, even the most potent poison would have been completely eliminated after being diluted and degraded over such a long distance.

"This is not ordinary poisonous water. No life emerged even after pouring the omnipotent potion into it. This means that there are not even the smallest microorganisms in it. It is truly 'dead water'. We are definitely not wasting our time in vain."

It was not obvious in Taki Country. Even after diluting the water samples countless times, one could still barely find a small amount of bacteria. The water samples found in Frost Country even made Mizuki a little confused. There was actually water in the Ninja World where even bacteria could not survive. If it was not for a very purposeful and targeted search, who would notice that these waters that seemed normal at first glance were so different.

"Biological toxins cannot be transmitted over such a long distance, but there are no signs of human intervention. I guess it is a special energy-like substance dissolved in water that is at work."

"Well, hopefully there will be some discovery."

Nobumasa, whose main task is observation, should currently focus on the village, especially on Haruno Sakura. He should not only monitor the changes in Sakura after she practices controlling the chakra of the tailed beasts, but also ensure her safety.

In addition, it is also necessary to pay attention to Danzo and his subordinates.

It's really not a comfortable thing to abandon important things and come to such a cold and hellish place.

After a while, the busy Yongjie finished testing the last water sample in his hand and said with some satisfaction:

"It's not far. What we are looking for is right in front of us."

"This is the third time you've said that."

Yusuke pointed to a hilly area ahead.

"Look there with your white eyes!"

"knew!"

Xinzhen formed seals with his hands, opened his Byakugan again, and glanced in the direction Xinzhen was pointing.

"There's nothing there, just an underground river and a huge cave. The underground of a small hill is basically empty, but there's nothing inside... Hey, that's not right!"

Xinzhen suddenly stopped talking casually, and an incredible look suddenly appeared on his face.

"There are things underwater, so densely packed that I can't even count them."

Involuntarily, Xinzhen quickened his pace and moved quickly towards the place where the abnormality was discovered.

"Be careful, beware of danger!"

"Don't worry, it's still a long way to go!"

Ninjutsu with a wider detection range than the Byakugan is not something you can come across easily, so the safety of the two should be guaranteed.

A moment later, Xinzhen, who was hiding in a snow-covered evergreen bush, could no longer hide the shock on his face.

"What did you find?"

Yusuke asked with some curiosity.

"White Zetsu, so many White Zetsu clones!"

"White Zetsu clone? You mean..."

Hearing the unexpected answer, Yusuke was suddenly shocked.

"Is this the underground base of Uchiha Obito and White Zetsu, the arsenal for training a 100,000-strong White Zetsu Army?"

It was truly an incredible discovery. After such a painstaking investigation, I unexpectedly found the enemy's lifeline.

"This is a hornet's nest, do you want to poke it?"

Xinzhen shook his head.

"Let's see first."

Even the strongest Fire Nation cannot resist such a powerful force alone. Before the five major ninja villages mobilize their war machines with all their strength, 100,000 White Zetsu are currently invincible. Such a large number is enough to destroy half of the ninja world.

"I should have thought of it a long time ago. The main battlefield of the Fourth Shinobi World War is in the Frost Country, and the base of the White Zetsu Army will not be far away."

According to Mizuki's memory, when Uchiha Obito launched the Fourth Ninja World War, most of the battle formations were deployed in the southeast of the Frost Country, with a small part in the Land of Rice and the Land of Iron.

Nearly 200,000 people fighting in this small area will be a grand scene that may never happen again in the ninja world in the future.

To the southwest of the Frost Kingdom is the Taki Kingdom, followed by the Grass Kingdom and the Rain Kingdom. To the west of the Rain Kingdom is the Stone Kingdom, to the south is the Wind Kingdom, and to the north is the Earth Kingdom.

Nagato and Uchiha Obito did not trust each other, and their bases were separated by two countries, thousands of miles apart.

"It's really spectacular. One hundred thousand White Zetsu. If someone has trypophobia, he would probably faint."

Under the observation of the White Eyes, the situation inside the underground cave was clearly visible. Rows of White Zetsu stood at the bottom of the underground river, waiting quietly.

"So, the source of this strange poisonous water should be here? No wonder it is so mysterious. With our knowledge, we can't find any clues. It's not surprising that it is related to this kind of thing."

After observing carefully for a moment, Xinzhen continued.

"Neither Zetsu nor Obito are here, but there are barriers protecting the surroundings. It's a bit difficult to sneak in without being noticed. Besides, those White Zetsu clones under the water are also awake, and we can't avoid their perception. Let's go back this time and make a long-term plan before deciding what to do."

After recording the situation inside one by one and understanding the situation reflected by the chakra, the two quickly left the place.

As night fell, a snowstorm came unexpectedly. Snow flakes fell one by one, covering all traces. The spring of the Frost Kingdom had not yet arrived...