I know this is a kids' show, but this is one of the best Transformers seasons ever produced.
Episodes 1-4 follow up on the end of season 2, with the Autobots returning to Cybertron.
Episodes 5 then starts a new arc (which will last 13 episodes), with the (Matrix-like) Quintessons having already conquered Cybertron. This arc culminates in episodes 14-17, in which a second Titan is revived, fights the first Titan, and Megatron returns with one eye missing and somehow in possession of a Matrix of his own.
The final block of episodes (9 total) begins with episode 18, which establishes the new status quo, with Autobots and Decepticons splitting the planet between them, while Bumblebee seeks to find Windblade, who was lost in the climax of the previous arc. Episodes 19-26 mostly follow Bumblebee and Chromia as they attempt to find the splintered parts of Windblade's consciousness, leading to several episodic adventures -- some of my favorites. It all culminates with Optimus abruptly deciding to destroy Megatron's Matrix, culminating in a conflict with an alternate-universe Megatron known as the Other One. While the ending is rushed, it's pretty good stuff.
Beautiful sets, costumes, music, and shots. I was blown away by this at the time and like it only slightly less today. How does Paul Rudd look like only five years older today?
