After acquiring dark energon, the Decepticon leader Megatron works tirelessly to uncover its secrets in an effort to finally wield its great power! Now it's up to the heroic leader of the autobots, Optimus Prime, to stop his old nemesis once and for all, no matter what the cost. But Optimus Prime will not only face Megatron in this ultimate rematch, but rise to the challenge of defeating an even greater foe - Unicron, whose power threatens the existence of humankind.

Episode List:
21. TMI
22. Stronger Faster
23. One Shall Fall
24. One Shall Rise Part 1
25. One Shall Rise Part 2
26. One Shall Rise Part 3