The story centers on Mizutani Masayuki, an ordinary high school boy. His classmate Shimizu Sayaka lives in his home as a zealously intrusive maid, leading to uncomfortably erotic situations.

The story focuses on high school girl Nagisa Yukiai who lives in a seaside town. She has believed her grandmother's story that spirits dwell in words and they are called "kotodama" (word spirit). One day, she strays into a mini FM station that has not been used for years. As an impulse of the moment, she tries to talk like a DJ using the facility. But her voice accidentally broadcasted reaches someone she has never expected.

The year is 1983. The Cold War is in full effect, and humanity is under attack. Strange aliens, given the name "BETA," have descended to Earth with the goal of destroying all life. Soldiers have been tasked with piloting large combat suits called Tactical Surface Fighters (TSF) to repel the alien invaders, but the front line is slowly being pushed back towards the surviving cities. Schwarzesmarken follows the story of Second Lieutenant Theodor Eberbach and the other members of the 666th TSF squadron, a ruthless unit that values a mission's completion over human life. Stationed in East Germany and led by war hero Captain Irisdina Bernhard, the unit specializes in counterassault attacks on laser-class BETA. But the 666th squadron finds itself with more enemies than just the alien forces when optimistic rookie Katia Waldheim joins the squadron, drawing the attention of East Germany's secret police, the Stasi. [Written by MAL Rewrite]

Following the conclusion of the first ever Squad Jam, Pitohui is eager to see what she missed, dying to know how everything went down. To satiate her desires, M reviews footage of the competition with her, commentating on the trials that he and LLENN faced together. [Written by MAL Rewrite]