This series began with a three-episode story, later titled either More than Meets the Eye or Arrival from Cybertron. In this incarnation the planet Cybertron is running low on energy. The Heroic Autobots, led by Optimus Prime, set out in space to search for more energy but are attacked by the Evil Decepticons led by Megatron. Both races crash on Earth and lie in suspended animation for the next four million years. Awakened by a volcanic eruption, the computer on board, Teletraan I, begins repairing Decepticons and Autobots. The Decepticons set out to plunder Earth's energy resources in order to have the energy to conquer Cybertron. The Autobots seek to prevent this and so the battle is renewed on Earth, Cybertron and across space.
After sixty-five episodes across two seasons, the status quo of the series received a major shift with Transformers: The Movie, which then led into seasons three and four (although season four comprised only a three-part miniseries). However, as the movie was not shown in Japan until 1990, a special episode was written and animated to bridge the gap between the 2nd and 3rd seasons, titled Scramble City, detailing the creation of Metroplex. A second Scramble City episode exists which retells the first, but in stop-motion animation, rather than cel.
Leaders come and go as the years pass. In the fourth and final series, comprising a three-part story titled "The Rebirth", Cybertron is revitalized using energy from the Earth's sun. The Autobots and Decepticons have discovered the world of Nebulos and united with rival groups of Nebulans to become Headmasters and Targetmasters. However, this three-parter was not aired in Japan, where it was opted to continue the Transformer series with further full-length seasons (see below).
When the line was relaunched in the 1993 as Generation 2, the 1984-92 era was retroactively branded "Generation One" by fans, a term that was later adopted for official use. It formed the basis for all Transformers series to come.
The comics produced by Marvel between 1984 and 1991, and again from 1993 to 1994, tell a substantially different version of the story. Both versions were equally authorized by Hasbro. (Wikipedia)