Rise of the Otherworld.

After leaving the dangerous place, Lin Yu and his companions found a quiet valley as a temporary resting place. The valley was shaded by green trees and a gurgling stream, creating a peaceful and tranquil scene. However, everyone's thoughts were not on this beautiful scenery at all, but on the mysterious secret book in Lin Yu's hand.

Lin Yu couldn't wait to open the secret book given by the old man. He saw that the words on it were ancient and obscure, like a puzzle that had settled in the long river of time. Those words were crooked and varied in shape, full of mystery, as if telling ancient secrets.

"What kind of skill is this?" Lin Yu frowned, lost in thought. His eyes were fixed on the words on the secret book, trying to find a clue from it. The sweat on his forehead slid down his cheeks and dripped onto the yellowed pages.

Xiaoyaozi came over and took a look at the secret book, his face also bewildered. He stretched out his fingers and gently touched the words, as if trying to understand their meaning through touch. "Master, this book is so mysterious, I'm afraid it won't be easily understood." Xiaoyaozi said, his voice tinged with worry.

Lin Yu nodded: "But this is a rare opportunity, we must find a way to understand it." His eyes were firm and full of determination.

So, everyone gathered together and began to study the manual. Everyone was focused, their brows furrowed, and they frequently shared their thoughts. Time passed, and no one had a clue. Their eyes, once filled with anticipation, gradually dimmed, and the atmosphere grew increasingly gloomy.

Just when everyone was feeling frustrated, Lin Yu suddenly had an idea. His eyes suddenly lit up, like a shooting star across the night sky.

"I think I understand something!" Lin Yu said excitedly. His voice broke the silence and cheered everyone up.

He pointed to a pattern on the manual and began to explain his discovery. "Look, the lines in this pattern seem to be similar to the trajectory of spiritual energy we're familiar with." His fingers traced the lines of the pattern, his expression focused and excited.

Everyone listened attentively, as if they saw a ray of light in the darkness. Their eyes were fixed on the pattern pointed by Lin Yu, and their minds kept thinking about his explanation.

After some discussion, they finally gained a preliminary understanding of the secret manual. "If we can practice this technique, our strength will definitely increase greatly!" one disciple said excitedly, his face filled with an expectant smile.

However, the cultivation process was not smooth. As they began to practice according to their initial understanding, they encountered one difficulty after another. The flow of spiritual energy within their bodies was often blocked, and waves of excruciating pain in their meridians made them suffer unbearably. Progress was extremely slow, and their initial enthusiasm was gradually eroded by repeated setbacks.

Lin Yu was extremely anxious, but he was helpless. He kept flipping through the secret book, trying to find a solution to the problem. At night, when everyone else had gone to sleep, he was still studying alone by the campfire.

Just when they were about to give up, Lin Yu stumbled upon a crucial clue. While observing a flying bird in the valley, he suddenly recalled a description from the secret book. He hurried back to the group and shared his discovery with everyone.

"Maybe this is the key to our breakthrough!" Lin Yu's voice was full of hope.

Can they use this clue to successfully practice the mysterious skills and embark on the path of greatly increased strength? The future is still full of unknowns.