Transformers: Energon (Film)

Transformers: Energon is the second installment of the Transformers Unicron Trilogy reboot film series, which began with Transformers: Armada. It is a science fiction action war film based on the Transformers franchise, more specifically the 2004 series Energon.

Plot
Ten years since the death of Megatron and the defeat of Unicron, Autobot leader Optimus Prime has been living in exile and his position has been filled by Rodimus Prime. Meanwhile, another disgraced Autobot, Sentinel Prime, has stumbled across the dormant Unicron, who has been floating lifelessly through space since his defeat. Sentinel begins to rebuild Unicron, and unleashes a group of Terrorcons which attack Cybertron, stealing from it's Energon reserves. However, as he renergizes Unicron, he also ressurects Megatron, who's body has been lying inside of Unicron since his fatal fall. Sentinel then recreates Starscream, but Megatron makes him his loyal servant. Megatron then chases Sentinel into Unicron's head and takes over his body as his new base. He reorganizes the Decepticons under his leadership.

When the Decepticons launch an attack on Earth's back-up Energon reserves, Rodimus heads a counter-attack. They ultimately prevail and the Decepticons retreat, but Rodimus is badly damaged and shuts down. Just when it looks hopeless for the Autobots, Optimus returns, agreeing to return to his previous position in their darkest hour, but states that he will retire once more after they have defeated the Decepticons.

Megatron locates a Dark Energon silo on Cybetron's sub-levels and launches an attack. With the silo under siege, Optimus mounts an assault against Unicron, hoping to destroy him once and for all. After a deadly battle, they destroy his body and head, killing Sentinel. On Cybertron, Megatron wins the battle but is badly wounded. He then jumps into the silo and reemerges as the newer, more powerful Galvatron. However, Unicron's mind still lives on in Galvatron.

Galvatron attacks the Autobots base and is confronted by Optimus. Their battle escalates into space, with Unicron driving Galvatron more and more insane. Optimus confronts Galvatron with this knowledge, who declares himself better than Unicron and flies into the sun, destroying himself and Unicron. A desperate Starscream pursues him and is also killed. With Rodimus still comatose, Optimus agrees to remain in charge until he is nursed back to health.

Sequel
The film was followed by Transformers: Cybertron.