21 parts Complete Battle was not foreign to Firefly.
She wasn't from Earth or Cybertron, Firefly was born on a planet called Zenthara, where her father and her were the chief protectors. She had been trained for war since the death of her beloved mother. When the Great Exodus sends Autobots and Decepticons fleeing from Cybertron, Zenthara becomes ground zero.
During a battle with the Decepticons, Firefly finds herself knocked out and in an enemy prison, where she meets Autobot rookie, Smokescreen, and escapes with him to Earth.
Optimus and Firefly had duties to protect their people, and in the upcoming weeks, they will both experience the greatest of failures, the darkest of times, and hope seems lost forever. Together, they must pull through and forge a new age, but as the war rages on, that goal seems further away than ever.