The Basic toys dropped the spring-loaded autotransformation in favor of more complex manual conversions. The "Mutant Heads" feature was dropped from the larger size classes (save for the old-mod redecos/ retools , of course). Instead of hidden mini-animal partners, this year the Mega class toys had extra "attack modes" that revealed new play gimmicks. The Ultra class toys are not super-huge robots, but teams of three smaller robots who combine into a super-huge robot. (These were also the first new-mold combiner toys (in the US at least) since 1989 .)
The Nemesis has proven to be powerful and dangerous under the now-insane Megatron, killing both Maximals and Predacons alike. Tigerhawk is destroyed with a large energy cannon, and Inferno and Quickstrike both get killed in Megatron's whimsical attempt at taking out a group of proto-humans. Optimus fights Megatron alone, while Dinobot II decides to aid the Maximals by sending them data about the Ark (a consequence from his spark now being independent, which apparently allows him to think more for himself and like the original Dinobot, though the episode hints that Dinobot II has become a conduit for the memories of the original Dinobot from beyond the grave as he recalls the last words spoken to the original Dinobot from Code of Hero, though this is never outright confirmed. However the clone loses the metallic echo his voice originally possessed upon his creation and begins to show signs of Dinobot's personal code of ethics, citing the concept of honor, which up until that point the clone did not care about, to Megatron when he is about to unleash Nemesis' firepower on a single proto-human after physically stopping him from opening fire on him). The Maximals receive the data and discover an Autobot shuttle in the Ark , which Rhinox flies and crashes into the Nemesis control tower, taking out Megatron as it goes all the way through both sides. Optimus flies away while Dinobot II bids farewell and goes down with the ship. The Nemesis is now out of control and flies off toward South America, where it would be discovered during the Great War. The Autobot shuttle and the Transformers on board are safe to resume their original place in time . The Maximals return to Cybertron triumphant with Megatron as their prisoner.
In their first appearance in the Generation One series, the Dinobots were dispatched to Earth to discover what had happened to the missing Ark . They encountered the Decepticons, who would become the Insecticons , and both sides blasted each other into stasis lock. The Dinobots killed Octane and stole his ship, but they ran into trouble when the local Autobot forces believed them to be traitors and fired on them. Repaired by the Autobots, who were by now convinced of their intentions, they participated in the final assault on Shockwave, where Grimlock rescued Magnus and Optimus Prime.