The protagonist travels back to the Qin Dynasty and becomes a dying soldier guarding a small border town. This is a real and cruel ancient world, where the wheels of history are rolling forward, and there are also unknown things hidden in the shadow of history (such as ancient ruins, strange beasts, and the secret skills of alchemists). He discovered that this was not a simple ancient time, but a "sandbox world" where history kept repeating itself in a certain "pattern".
