"Top o Nerae 2! Diebuster" follows the story of Nono, a country girl who dreams of becoming a space pilot (or, to be more precise, "like Nonoriri", the meaning of which is revealed as the series progresses) who, due to a chance encounter with an "actual" space pilot, finds herself becoming part of the elite "Fraternity". Made up of teenage pilots called Topless, and armed with quasi-humanoid weapons called Buster Machines, the Fraternity's mission is to protect the people of the Solar System from attack by swarms of space monsters.