The Construction of Technology and Magic 1

Thousands of years ago, a passage (people called it the Avenue) to another world appeared somewhere in the south. The empire of this world established diplomatic relations with the ancestors of China and promised to help the empire when it was in danger. However, thousands of years later, the empire was attacked by the coalition forces of various countries, and the highway was closed for some reason, making it impossible for the empire's diplomats to go. However, the encounter between a little girl and the daughter of the imperial king will start a new diplomatic relationship.