In this post-nuclear war world, four guys find irradiated suits of armor and set of to rebuild a shatter US and world. Snce it's post-nukewar. they find all kinds of things. The Rockies have become a chain of active volcanoes, which they must overfly in gliders since the indurstrial base of the US has been...well...nuked, including the oil industry (I can just hear the "cockroaches are indistructable so how can that happen?" jokes). They also take on invaders from Atlantis who use solar powered "mirror guns" to shoot really nasty heat rays to which our heroes' medieval armor, having been irradiated in some undisclosed way, is invulnerable. Since this is post-nukewar there are the usual kinds of mutants

Don't let this stop you if you can find them. The fun factor, including the pseudo-science, outweighs the hokum factor, aided by the exotica that they encounter along the way.