Humans' "Self-Defense Forces" have long been troubled by a shortage of manpower, so they adopted animals as a solution. As a result, the "Self-Defense Animal Corps" was created. However, in order to protect their own rights, the animals declared independence as a nation. In this context, the "Self-Defense Animal Corps" became an organization for animals. They sometimes get along with humans, sometimes don't, and they know that they are no match for humans in terms of military strength, but they maintain their independence. They occasionally hold joint training sessions. They were educated by humans, so they are said to be similar to human soldiers, but this is a story about animal soldiers who live happily every day without really understanding why.