In the near future, large mechs called Labors are made to assist in various reconstruction projects in major countries around the world that are being threatened by global warming. In Japan, the government has enacted Project Babylon in order to conduct land reclamation. Labors are also being pressed into police and military service, aside from civilian use.

However, terrorists are now attempting to use Labors to make themselves heard, as well as common criminals, thugs and guerrillas. The National Police Agency established the Special Vehicles Division, an all-Labor task force to combat the potential use of Labors for criminal/terrorist activities.

This title received the 36th Shogakukan Manga Award for shounen manga in 1991.