Duty After SchoolEP 01

One day, unknown sapphire-blue spherical life-forms suddenly appear in the world, posing a deadly threat to humanity. Medium-sized spheres can injure people, while smaller ones actively attack. In this crisis, high school students across the nation are placed under military training and organized into reserve forces, taking up arms in every region. Their mission is to defend their cities, destroy the small spheres advancing toward urban centers, and hold the line against an alien invasion.