Now to the description and a clip from the movie that was shown at the San Diego Comic-Con. Definite SPOILER WARNING as it will reveal some of the details on the finale of Transformers Prime.
Seriously, I am warning you. I don't use spoiler warning as freely as many sites so when I do its a clear signal to bail if you hate spoilers (course this site is technically a spoiler site...)
A resurrected UNICRON has taken over the now-lifeless body of MEGATRON to seek vengeance on the AUTOBOTS and ultimately, the destruction of Cybertron. This formidable enemy forces an unlikely alliance between the AUTOBOTS, DECEPTICONS, PREDAKING and two new Predacons, who come together in an epic battle to help protect their newly restored planet!