The island you thought was safe is a military installation pretending to be a town. Every kid who climbs into a Fafner isn't a hero, they're already dead, just delayed. You watch them understand this slowly, then live with it anyway, and that's where the show breaks you.

A quiet island in rural Japan hides a grave truth. The students of Tatsumiyajima grow up believing their lives will stay calm and uneventful, but their home is actually humanity's final line of defense against a hostile, incomprehensible enemy. One day the young islanders start receiving a strange message asking whether they are there, and after they answer, the enemy arrives in a flash of light. Facing a seemingly hopeless future, a boy named Kazuki Makabe chooses to pilot a Fafner, the giant robot that guards mankind's last treasure, in order to survive.