Disaster from the Sea
Twelve years ago, Japan was attacked by a Heterodyne, a mysterious monster that seemingly appeared out of nowhere. In response, 21st century Security built a giant robot called Dai-Guard to combat the Heterodyne, but by the time it was ready, they had disappeared again. Turned over to the company's PR division, Dai-Guard has since become little more than a tourist attraction. However, when the Heterodyne reappear, PR Division worker Akagi Shunsuke is insistent that he and his co-workers should pilot the robot for the purpose it was meant for. But can a trio of untrained office workers really hope to save the world in a cheaply built old robot?
Aired 05/10/1999EP 1 - Disaster from the Sea

Dai-Guard
Thirteen years after their sudden disappearance, an alien race known as the Heterodyne resurface without warning. To combat the Heterodyne, three office workers from the 21st Century Security Corporation operate Dai-Guard - a giant robot no longer regarded as an oversized paperweight. Unfortunately, Dai-Guard is somewhat obsolete and in disrepair. It's a tough job, but salarymen can also save the world.
(Source: Anime News Network)