Transformers: Robot Masters

Robot Masters is set after Season two of the original Transformers series. In it, the original Megatron has been lost in some undisclosed accident, and the Autobots (Cybertrons) are in development of technology that would allow them to harness the power of a new energy "Solitarium." Through some unknown event, Transformers from all over time and space begin arriving in this time period through phenomenae known as "Blastizone." Beast Wars Megatron (referred to as Beast Megatron) would arrive, and claim leadership of the Decepticons (Destrons) from Starscream. This conflict would progress, until the arrival of Reverse Convoy, a Transformer hailing from the planet Vehicon, who, in reality, was a rebuilt Megatron having been transformed into "Rebirth Megatron". They would all eventually be defeated, however, and the various Transformers returned to their own time.