Tom Selden and Luana Patten are young, in love, and no longer willing to wait. So they hop into his Plymouth and head to the Mexican border, to get married. But the car runs out of gas, and the next thing they know, Steven Marlo is knocking on the car window. His motorcycle conked out a couple of miles down the road; the spark plugs are bad. He'll walk to the nearest gas station, get some spark plugs and gas, and they'll give him a lift back to his bike. But the motorcycle doesn't turn over, so he rides with them a bit further. At the next stop, he murders a blonde woman in a rage, hides the corpse, and goes on with them. It's his second murder within the latest day, and the cops are already on his trail.
There's a great deal to do in this movie's 61 minutes, and as a result, little of it is done satisfactorily. We watch as Marlo's mind grows more and more unhinged, with Selden and Miss Patten increasingly helpless. We watch as the cops pursue and debate, not just why Marlo is that way, but that it's getting worse; in twenty years they'll have the tools, but what do they do now? None of the answers are satisfactory, none of them solve the problem, and that, my friends, is the subtext of this movie. You're supposed to watch it and be disappointed, dissatisfied, terrified.