The story revolves around a new team of "Toei robot girls" named "Team Z" that is made up of three girls based on Toei's Mazinger Z franchise: Mazinger Z, Great Mazinger, and UFO Robot Grendizer. Usually they perform in activities around Nerima ward in Tokyo to raise the awareness of the promising future energy source "Photon Power." However, there are times when "Mechanical Beast" team of girls emerge from the "Subterranean Empire" and attempt to steal the energy. Thus "Team Z" has to battle them to prevent this, though sometimes they just go and beat up the "bad girls" to relieve stress.

Mazinger, later called Mazinger U.S.A. Version or Mazinger U.S. Version to avoid confusions with the rest of the Mazinger works, is a 58 pages long manga created by Go Nagai specifically for the US market. It features full-color graphics, text in English and left-to-right formatting. It is partially inspired by Gulliver's Travels. http://mazingerzgreatkaiser.wikia.com/wiki/Mazinger_U.S.A

Great Mazinger starts after the defeat of Mazinger Z. Tetsuya Tsurugi is the new protagonist, piloting the powerful Great Mazinger, a creation of the once thought dead Kenzo Kabuto, the father of Koji Kabuto. This time the enemy is the Mycene Empire and its powerful robots.