The series is based around three office workers of the 21st Century Defense Corporation who, with the company's giant robot, Dai-Guard, fight interdimensional alien beings called heterodynes. Unlike most giant robot anime, Dai-Guard performs on much more realistic physics, making it heavy, slow and a hassle to control. Also, the heterodynes seem to be the least of the 21st Century Corporations problems as they experience opposition in the form of massive damage claims, lawsuits, rivals and a jealous and antagonistic military who wishes to take back Dai-Guard for themselves.
