Transformers Prime "A Lost Soldier"

Three years after their last confrontation with Decepticons. Optimus Prime and his team have stayed on earth in a base located in a converted missile silo in Nevada. No one knows of their existence other than the government, and three kids.

The fight with the Decepticons is becoming harder for them to deal with and now with three new members, they are learning more about the destruction of their home and the people they love.

What will happen when Jack, one of the humans, meets a unknown Autobot, who doesn't want Team Prime to know is alive? Will she help Team Prime or will she become an enemy? And why does no one want to tell Jack about her?