What do you see when you look up at the sky? A blue expanse? Freedom? A hopeful future? The people of Tokyo see none of these. Instead, an ominous alien mothership looms overhead, engulfing the city's skyline. Three years ago, they arrived. The coming of the "Invaders" sparked the greatest war humanity had ever faced—one that threatened to end the world. The Japanese government scrambled to fight the Invaders. Weapons were mass-produced, sparking controversy and pacifist movements. That day, everything changed. And yet, nothing has changed. Kadode Koyama and Ouran Nakagawa live their final days as they always have: going to school, playing with friends, and doing what any carefree high school girl would do. As they grow up, they come to learn what it truly means to be an adult, in a world where adults seem to be demons who only deceive and destroy. They come to learn the real threat to humanity is not the Invaders, but humanity itself.