First there were the dinosaurs. Horrendously big and terrible. No one's quite sure what happened to them, but we're pretty sure they didn't have much say over it.
Then came humankind. They did a great job of making all sorts of stuff, but eventually, their power exceeded their wisdom. Despite the warnings from many movies and books, they managed to exterminate themselves. Quite quickly, actually.
The only critters to escape the devastation were rodents and insects. A great silence settled across the earth.
Over millions of years, the last denizens of earth evolved to the point where they speculated about the weather, argued over property lines and bet on dragonfly races - the hallmarks of civilization.
Now, the Rat Empire, under the rule of Imperious Rat, extends its claw-fingered grip across the continent of Rodentia. The Empire's unrelenting growth tramples the innocents under its boot-clad heel. One beaver stands alone in his quest to emancipate beaver-kind and all rodents who yearn to be free... Deathbeaver