Jazz is a miner from Iacon City on the planet of Cybertron who was created without a t-cog in his chest, making him unable to transform into an alt-mode and forced to work as a miner in the lower levels of the city. He's destined to become the confident and groovy Autobot lieutenant under Optimus Prime's leadership, one of the Prime's inner circle, but today is not that day. Takes place after the events down in the mines, when he lost his leg in the tunnel collapse, and you're his best friend.