From Anime News Network:
"In commemoration of the 50th Anniversary of the Treaty of Mutual Cooperation and Security between the United States and Japan, Headquarters U.S. Forces Japan has developed a Manga Comic entitled “Our Alliance; A Lasting Partnership” to highlight this historical landmark.

The Manga describes the U.S. Japan Alliance and how the U.S. military plays an important role in this relationship. Focusing around the two main characters Arai Anzu, a Japanese girl, and Usa-kun, a boy visiting Japan from the United States, the two explore and learn about the U.S. military in Japan and its role in the U.S. - Japan Alliance."