After this disaster, work was started to build a giant robot, Dai-Guard ("Big Guard") to protect against further attacks by the Heterodyne. But no Heterodyne appeared for a long time, and the military offloaded the robot, which had turned into a money-pit, over to a private company, called 21st Century Defence Corp., an insurance and security company. Dai-Guard became a company mascot and has been delegated to the Second Public Relations Department.
And then the Heterodyne appear once again! The clerks of the PR department have to use Dai-Guard to defeat the monsters!
It would be typical mecha-anime, if not for the fact that this robot is owned by a company. We get such lines as "No! Don't start up Dai-Guard! The proper forms have not been signed by our supervisors yet! It costs more than a month of your salary to start it up!", and afterwards there are lengthy reports to be written by the pilots. And then the military comes into view as well. They seem to regret having sold the robot to the company, because now a bunch of civilians are defeating the Heterodyne, leaving the SDF standing by the sidelines.
By episode 7, the story isn't about the Heterodyne anymore -- it's about the internal struggles in the company and the friction between the military and the civilians. It gives a nice view behind the scenes of Japanese office workers (though I can't determine whether it is a truthful rendition of office life or not), and the banality of expense reports offsets the heroic escapades by the brave pilots of Dai-Guard.
It's too bad there isn't some sort of conclusion to the series. OK, there's this really big Heterodyne to defeat, but there is no indication that the Heterodyne have been defeated for good -- it'll just go on.
I'll give it a 7.5 -- most of that because of its originality.