"From the minds of mortal men, the mightiest of machines ...TRANZOR Z. With all the might, he fights for right. He's a protector of peace so powerful, he can not be destroyed ...TRANZOR Z" (opening narration)

Piloted by Tommy Davis (who lands a hovercraft into the head of the tobot), TranZor Z battled the sinister Dr. Demon and his hordes of robot beasts as they attempt to take dominion of the planet Earth.

The weapons of TranZor Z include:

• Missiles fired from its elbows and fingertips
• Powerful fists
• Shots Photon Beams from its eyes
• Powerful blasts of energy called the Breast Fire.
• Rocket pack called the Jet Scander that makes it fly.

Other characters on the series were:

• Dr. Davis, the new head of  the Volcanic Research Institute
• Tommy's grandfather, the former director of the VRI who was murdered.
• Jessica Davis, Dr. Davis' daughter who pilots the robots Aphrodite-A
• Toad, Tommy's little brother
• Bobo, who maintains TranZor Z with the help of Jim and Chris
• A team of three professors (one named Dr. Manning) who help upgrade Tranzor and Aphrodite. At Bobo's request, they built him a robot called BoboBot.
• Dr. Demon, who wants to destroy Tanzor Z and take over the world
• Devleen, Dr. Demon's 1st Lieutenant henchman (half man/half woman) who commands the Iron Mask Warriors.
• Count Decapito, Dr. Demon's General who carries around his head.  
• Ghengis, Dr. Demons evil rival, who eventually assumes command when Dr. Demon dies. Note: He stars in the second Tranzor Z series, Great Mazinger. The second and third series (UFO Robo Grendizer)  never aired in the United States. 

In the Japanese version ("Majingâ Zetto") Dr. Davis was Professor Juzo Kabuto; his grandson was Kouji Kabuto, Dr. Demon was Dr. Hell and Devleen was Baron Ashura.

At the finale of the first series, Tommy, Tranzor Z, Jessica, Aphrodite-A, and the Bobobot destroyed Demon's island as well as Dr. Demon and Decapito who were escaping in an aircraft.

Unfortunately, TranZor Z was destroyed and a new and improved robot was introduced as the Great Mazinger. The original TranZor Z was constructed from Chogokin Z (Super-Alloy Z) that was forged from a new element (Japonium) found on Mt. Fuji.

Based on a 1970s amine created by Go Nagai, the half-hour Japanese animated series  ("Majingâ Zetto") was produced by 3B Productions and Toei Animation under the title In Japanese, the robot is called Mazinger ("God Devil") because like any tool, it can be used for good or evil.