Transformers Prime Theatrical Movie

This was confirmed by Jeff Kline that Transformers Prime was meant to get a theatrical movie planned to be released at the theaters. The storyline is unknown but it is believed to be about the original storyline after Season 2. The plot: Not much is known about the plot of the movie is but it's more likely to be more apocalyptic. It's possible that Unicron was trying to resurrect himself and needed a vessel in order to be able to search for something. The Matrix of chaos or the Dark Spark were two possibilities meant as plot devices and what Unicron is looking for. Or Megatron himself was going to use any of those two for his own agenda,a plot twist revealing that he was alive would have been perfect,especially if any of the two relics would have upgrade him into Galvatron.

Why is it cancelled?

If it was connected to the original plans,then it was cancelled when the plans changed or it was cancelled because of trouble with Aligned behind the scenes so they decided to change all the plans and finally end Tranformers Prime with Predacons rising. Possibly meant to be released in 2014-2015 but never happened. The movie's working title was meant to be Chaos Rising.