The place is Vietnam, the time is the height of the war there in the nineteen-seventies, and in an obscure corner of the jungle, a Christian mission has been attacked by the Viet Cong, scattering the locals and the remaining missionaries and authorities must flee on the school bus they have been using. A motley group of people assemble on the vehicle as the bullets fly, and the driver sets off, though is stopped by three American soldiers who demand to know what he is doing, for they have noticed he is travelling north rather than south, to safety. He runs away and one of the G.I.s takes off after him, dodging a grenade and gunning him down - now they must make their own way.
The Italian exploitation film industry had one desire: to make a bunch of profits by posing as Americans. Or that's how it seemed for great swathes of their product, and the Vietnam War flicks they produced in the eighties were no exception, a seemingly bottomless well of jungle-set explosion fests where jobbing American actors and a fair few European ones pretending to be American since with the dubbing nobody knew the difference anyway were dressed up in fatigues and given automatic weapons to fire as many blanks as they possibly could at a parade of local extras, themselves dressed up in appropriate uniforms though they were actually Filipino.
The Philippines was the go-to nation for your eighties jungle epic on a budget, as inspired by both the wealth of Roger Corman action flicks and Francis Ford Coppola's Apocalypse Now which had been the cue for many lesser funded movies to tap into the "war is Hell" mood of the eighties that the Americans were using to reopen old wounds, and in doing so giving them the chance to heal again with the power of earnest cinema. Certainly the imitators could do earnest well enough, but when it was plain they most wished to blow shit up as often as possible more than make a grand statement on the conflicts afflicting the globe, they were difficult to take seriously.
Fair enough, even in the most sober Vietnam efforts there was a tendency to fall back on the spectacle of either seeing actors riddled with bullets (or bullet squibs) or hire a pyrotechnician to create the oiliest explosions available, it got the adrenaline pumping for reasons that audiences may prefer not to examine too closely when the finger-wagging message was that war was bad and you should feel bad for being excited by it. There was no such ambiguity with items like War Bus or its plethora of likeminded contemporaries, here they were pretty blatant about setting out their table of guns and ammo and inviting the viewer to get off on watching them used as often as they could, and if you liked such unabashed macho entertainments you could have a fairly good time with a number of them.