Transformers: Unicron Free Comic Book Day

Plot

Optimus Prime, Bumblebee, and their friends must unite every Cybertronian, Earthling, and ally they have to stand against this threat to all existence. But why is Unicron hell-bent on destroying Cybertron? What original sin did Optimus Prime's ancestors commit to earn this wrath? It's an all-out battle against extinction as the world-destroying, universe-shattering threat of Unicron comes to end everything.