Abyss Tunnel

There is a mountain with a dilapidated temple on it. A tunnel appeared at the bottom of the mountain. A long, straight and dark tunnel. Once someone steps into it, they can never get out. Even if they come out, they are no longer human. The government has blocked it. Even so, it is still a forbidden land that many people are eager to explore. What is the mystery? This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.