Nobody talks about this one. The show builds a genuinely alien threat that doesn't need to be explained through anime conventions, the Atman are operating on completely different survival logic, and watching humanity scramble to communicate with something that thinks in geological time creates tension that most mecha shows never find. The wasteland setting strips away the usual school-life padding; every scene assumes you understand that comfort is gone, resources are finite, and the next discovery underground might be humanity's last mistake. It costs your time, but it pays back in slow-burn dread that earns its ending.

Early in the 22nd century, nuclear war leaves the Earth a wasteland. The few people who survive come together and build Setos, a city-state where they work on a plan to revive humankind. While that effort moves forward, they make contact with the Atman, lifeforms that have been sleeping deep in the planet's mantle. The series is a mecha science fiction action story set in this ruined world.