About a quarter of an hour later, Nie Fei and Li Ruoyun swam out of the underwater passage and arrived at an underground cave.

After going ashore, Nie Fei couldn't help but look at the surrounding situation, this was a closed underground cave, and there was no other entrance and exit except for the entrance and exit from the bottom of this pool.

In the entire underground karst cave, the waterhole occupies half of the area, and the remaining half of the land area is empty, only a closed stone door stands in front of it, as for what is behind the stone gate, Nie Fei can't know.

"Huh? Where is this? After Li Ruoyun went ashore, he also saw this stone door, and couldn't help but make a voice and ask Nie Feilai.

"I don't know where it is, but I'm sure there's a treasure behind this stone door!" Nie Fei touched his chin and carefully observed the stone door.

"Open it and see it, won't you?" Li Ruoyun walked over and directly stretched out his hand and pushed towards the stone gate.

Nie Fei was shocked in his heart, it was too late to stop it, but when Li Ruoyun's hand touched the stone door, nothing happened, Nie Fei secretly breathed a sigh of relief, it seemed that his worries were a little redundant.

"Huh? Why can't you push it away? Li Ruoyun pushed the door vigorously and asked questions.

"Oh? I'll give it a try. Nie Fei raised his eyebrows, walked quickly to the stone gate, and pushed the stone gate fiercely with both arms, but he didn't expect a golden light to flash above the stone gate, canceling out Nie Fei's strength!

"No, there's something wrong with this door!" Nie Fei exclaimed, and at this moment, some patterns suddenly appeared on the stone gate.

Take a closer look, a dragon-shaped carving appeared on the stone door, and around the dragon-shaped carving, nine round beads also appeared, and each bead seemed to be carved with a phoenix!

What's the situation? One dragon and nine pearls? Or is it a dragon and nine phoenixes? Nie Fei felt the bursts of energy coming from the carved patterns, and instantly realized that this was a formation! Someone has placed a seal on this stone door!

"There is a formation arranged on top of this stone door, and we can't open this door by brute force." Nie Fei said in a deep voice.

"Don't you know how to form? Wouldn't it be enough to break it? Li Ruoyun seemed to have a lot of confidence in Nie Fei.

"Well, this formation is not ordinary, the dragon-shaped carving is the main array eye, and the nine beads are the secondary array eyes, at a cursory glance, I thought it only constituted a ten-square array, but as everyone knows, these nine beads form a nine-palace array by themselves!" Nie Fei frowned and analyzed carefully.

"In other words, this is a mixed formation combining the Ten Square Formations and the Nine Palace Formations!" Nie Fei finally came to a conclusion.

"Is it difficult to break this formation?" Li Ruoyun doesn't understand the formation, she only cares about whether she can break the formation.

"It's not very difficult, the key is that my comprehension of the Nine Palace Array has not yet reached home, and now it is indeed a bit tricky for me to break the formation." Nie Fei said embarrassedly.

"What then? Are we just staring at the treasure here? Li Ruoyun was obviously a little unwilling.

Nie Fei lowered his head and thought for a while, and then proposed: "I think this place is not bad, or we will retreat here, I will strive to comprehend the Nine Palace Formation to the Dacheng realm, and then open the stone gate to see what the situation is inside?" ”

"Well, there's no other way to do it now, come on! It's up to you! "Li Ruoyun doesn't matter, it's the same wherever he retreats and cultivates.

So, the two of them then retreated and practiced in this closed underground cave.

Li Ruoyun took out the stone tablet that Nie Fei had given her at the beginning, and comprehended the sword intent on the stone tablet, while Nie Fei took out a large pile of materials from the space ring and kept fiddling with the Nine Palace Formation......

Time passed unconsciously, and a month later, Nie Fei's comprehension of the Nine Palaces Formation reached the realm of Xiaocheng, he tried to break the seal on the stone gate, but in the end it ended in failure, there was no way, Nie Fei had to continue to choose to retreat and comprehend the Nine Palaces Formation.

I don't know from which day, Li Ruoyun entered the realm of selflessness against that stone tablet, even Nie Fei called her several times, Li Ruoyun didn't know it, Nie Fei couldn't help but sigh secretly: This woman is in retreat and cultivates, she is too crazy, and she deserves to be a natural sword cultivator!

Another three months passed, and Li Ruoyun's whole body erupted with a fierce momentum, and the true yuan hovering around her was like a sharp sword qi, which could crush the enemy at any time!

Depend on! This Nizi has broken through again! Her sword intent has reached the realm of Dacheng! Nie Fei secretly smacked his tongue, Li Ruoyun's talent in kendo is really too BT!

At the same moment, the movements in Nie Fei's hand stopped, and a perfect Nine Palace Formation was laid out by him, haha! The comprehension of the Nine Palaces Formation has reached the realm of Dacheng!

"Done?" After Li Ruoyun woke up, he felt the formation fluctuations coming from Nie Fei's side, and couldn't help but ask expectantly.

"Of course, I'm a peerless genius, and the small Nine Palace Array can't bother me at all!" Nie Fei froze.

"Well, the formation is all the way, you are indeed great." Li Ruoyun nodded thoughtfully and said.

"What do you mean? Except for the formation, I'm not good at anything else? Nie Fei asked rhetorically.

"After I go back this time, I think I have the ability to challenge you." Li Ruoyun blinked at Nie Fei.

"Damn! Don't think that if you comprehend Dacheng's sword intent, you can defeat me, I have a lot of hole cards in my hand. Nie Fei said a little humbly.

"Well, won't you find out if you try it?" How could Li Ruoyun not see Nie Fei's weakness? With Li Ruoyun's current strength, the two are fighting, and it is really not certain who will kill the deer?

However, Li Ruoyun will not fight hard with Nie Fei, this Nizi has basically been conquered by Nie Fei, how could he make a move on his lover? When she said this, she completely wanted to scare Nie Fei, who told Nie Fei to always take advantage of her!

"Let's put aside the competition in advance, let's open the stone door and see what treasures are inside, right?" Nie Fei quickly changed the topic, he didn't want to fight Li Ruoyun.

"Hmm." Li Ruoyun replied softly, and at the same time looked at Shimen's eyes, and became expectant.

Nie Fei walked to the stone gate and fiddled with it carefully for a while, only to see the dragon-shaped carving on the stone gate emitting a dazzling light.

Immediately after, Nie Fei's hands danced rapidly, constantly pressing back and forth on the nine beads, the first bead lit up with white light, followed by the second and third......

It wasn't until the ninth bead also lit up with white light that the nine white rays of light and the golden light on the dragon-shaped carving became one, illuminating the entire underground cave as bright as daytime.

"Haha! Get! Nie Fei clapped his hands, and then pushed the stone door fiercely, and with a soft 'crunch' sound, the closed stone door was slowly opened......