With its second trailer, Bumblebee expands beyond a heartwarming story of a girl and her robot to include the civil war raging on Cyberton. The fan-favorite Autobot even has a mission, from a Generation One Optimus Prime: "There is only one way to end this wear -- you must protect Earth and its people."

As seen Sunday in the teasers, the trailer also features a G1 Soundwave, who ejects the hunting-cat Ravage during his face-off with Optimus Prime. What's more, the new footage introduces John Cena's role as Agent Burns from the U.S. government agency Sector 7, who's informed by the Decepticon Blitzwing, "There's a war breeding on our planet, and if this criminal isn't found, that war may find its way here."

On the run in the year 1987, Bumblebee finds refuge in a junkyard in a small Californian beach town. Charlie (Hailee Steinfeld), on the cusp of turning 18 and trying to find her place in the world, discovers Bumblebee, battle-scarred and broken. When Charlie revives him, she quickly learns this is no ordinary, yellow VW bug.

Directed by Travis Knight (Kubo and the Two Strings) from a script by Christina Hodson, Bumblebee stars Hailee Steinfeld, John Cena, Jorge Lendeborg Jr., Pamela Adlon, Jason Drucker, Abby Quinn, Rachel Crow, Ricardo Hoyos and Gracie Dzienny. The film arrives Dec. 21.

RELATED: First Look at Bumblebee's New Decepticons