A bunch of badly dressed motherfuckers have a good huge apocalyptic punch-up till only a person survives, whereupon aliens invade, so mentioned survivor travels back in time (no they don't say how, set your arm down!
After all of the remaining leaders and the head are at simply click the next site safest stronghold, he starts butchering their elite mooks with his lightsaber, his bare palms, a blaster, and the Force.