Transformers Prime Beast Hunters: Predacons Rising

Transformers Prime Beast Hunters Predacons Rising is a 2013 American computer animated action adventure television film that concludes the Transformers Prime television series. It was first broadcast on Hub Network on October 4, 2013. After the Autobots victory on Earth, Unicron returns in possession of Megatrons body with the intent on destroying Cybertron, forcing Autobots, Decepticons, and Predacons to form an unlikely alliance to counter this threat.

Set on finding answers, Bumblebee leads Bulkhead, Arcee, and Smokescreen to track Predaking, who has taken refuge near the grave site of hundreds of Predacon bones, and ask his help in finding his two new brothers. However, Predaking refuses, having not forgiven the Autobots for destroying his brethren on Earth. Bumblebee, after interrogating Knock Out, leads the Autobots to the Decepticon fortress Darkmount to find answers, but they are soon confronted by Unicron in Megatrons body. The Autobots believe Megatron returned before Unicron corrects them. Unicron battles the Autobots, who are outmatched and are forced to the lower levels where Bulkhead, Arcee, and Smokescreen almost fall into a smelting pit. However, time bought by Bumblebee allows the Autobots to escape through a Ground Bridge portal. Unicron, enraged by his failure in his weak form, decides that he needs a greater weapon.Meanwhile, in the Theta Scorpii asteroid belt, Optimus and Wheeljack arrive in Ultra Magnuss ship where the AllSpark, which itself is pure energy stored in a container of Alpha Trions creation, is adrift. Optimus heads out to find it, but is soon troubled with a plasma storm. Despite Wheeljacks insistence to turn back, Optimus keeps going and eventually retrieves it, though their ship is damaged by an asteroid, and they set course of Cybertron. Meanwhile, the Autobots try to contact Optimus from the Nemesis, but the asteroid damage destroyed their transmitter, making the contact only one way. With Optimus not available and Ultra Magnus wounded in action, Bumblebee becomes the temporary leader of the Autobots. ........

Source: Wikipedia