The Time Defense Line: Code Name Dragon Scale

In 2077, humanity has mastered "time anchor" technology. By using residual energy at specific historical points, they can send "time defenders" into the past, but they cannot directly interfere with major historical events without triggering a "time storm." Nations secretly establish "time defense bureaus." Members of the "Dragon Scale Bureau" must enter historical settings without triggering a time storm, take on the roles of historical participants, such as soldiers, villagers, or technicians, and correct altered details to protect the original course of history.