Description: The Frost Neutral Special Zone was set up as a buffer zone between the great powers of the United States of Kardi and the Vilcar Empire. While it has been a success as a tourist destination, it has also been a place of constant incidents and conflicts due to the immigration of various tribes. The main character, Kai Sakaki, works as an investigator for the Trigger Detective Agency, which has an office in the neutral special zone. His purpose is to search for his girlfriend's childhood friend, Saina Yuzuri, who went missing in the last war. Meanwhile, he meets a girl named Milly who is reaching for the sky on a hill overlooking the city. Just like Saina before her, Milly is worried about a world filled with constant conflict and desires peace. This encounter greatly changes the fate of Kai, the Neutral Special Zone, and the world. The story of overcoming a lost past and walking toward the future begins here.