The Transformers have a complex and inconsistent history,, but they remain both alien and robot throughout.

The characters of Transformers One are firmly aware of the danger they pose, with even the most powerful Primes unable to weather a full-frontal assault from the overwhelming alien race.

The new animated Transformers movie is a prequel about Optimus Prime's friendship with Megatron, played by Brian Tyree Henry. Can it bring new energy to a well-loved franchise?