It's an Italian exploitation horror that was so popular during the 1970's, starring Franco Nero (the D is silent), Corinne Clery (if you're a gimper but this name escapes you, start from scratch), and David Hess (love the guy). So, Nero and Clery play Walter & Eve, a bickering couple on vacation near an empty mountain/desert/highway, shown in the first 5 minutes how they despise each other with Walter pointing his hunting rifle to Eve and Eve refusing to have sex with him:

We find out the source of their problem later; it's because Walter is a drunk and temperamental journalist getting to the position he's in now cause Eve's father owns the company he's working for. Eve, obviously, feels she deserves more than the bastard. This fight of theirs continues to the night when Walter opens their trailer door for a couple in the rest area while his wife is changing:

Which leads to more argument with her in this kind of state:

See? I wasn't kidding when I told you the humiliation would be done unwillingly on her expense, huh?

The next day, they continue their trip when they run into a hitchhiker, Adam (Hess), who had his car broke down. Walter tells Eve to ignore the guy but Eve wants to stick it to him and invites Adam in. At first, it looks like everything is fine until Adam notices Eve & Walter aren't actually in love. Adam starts making passes at Eve, much to Walter's wrath. Not because he loves her, but because his ego won't let any guy teasing any girl he couldn't even have. This leads to a fight between Walter & Adam which ends once Adam shows his handgun, revealing himself as an asylum escapee who robbed a bank, leaving his 2 friends and is now on the run.

Walter’s ego had enough of this BS and he stops the car, dragging Adam out for a fight. Walter, despite his anger, quickly overpowers Adam but the guy goes for his gun and stops Walter, letting him know he’s in control now. Hell, he even makes sure of his role by revealing Eve’s underwear. (That’s one way to tell everybody you're the boss, BTW. LOL). Long story short, they're stuck with him. Either they take him to Mexico, or he shoots them.

As the movie progresses, it's clear there's no protagonist in this movie. With the exception of maybe Eve, but later it turns out she’s not actually the good wife either so I guess I won't call her good. Everybody is selfish and thinks only of themselves. It's nice for a change of pace where nowadays the horror movies are filled with stupid good guys or lame bad guys. Halfway through the movie, the 2 guys who were part of Adam's team caught up with them and attacked them, presumably killing Adam. But later Adam came back and disposed of them, all the while having Eve & Walter in the middle.

The climax (pun intended) came when, the night after killing his former friends, Adam decides to have his way with Eve after Walter mocked him for being an insane psycho. So, he has Eve naked, lying on the desert with Walter restrained across them, before he gets on with it:

What starts as a rape, suddenly takes a turn Straw Dogs style when Eve replies to Adam's advances:

We see Eve & Walter exchanging looks. Walter puts his head down, but more than likely because he's finally sure there are no more feelings between him and Eve. Once they're finished, Adam boasts to Walter how good a time he showed Eve:

Adam & Eve return to the trailer (giving Walter a chance to escape his ropes) before Adam returns to mock Walter, but Walter casually returns the words and angers Adam. Before Adam can shoot Walter, however, Eve shoots Adam from behind the trailer with Walter's hunting rifle, killing him:

Walter & Eve regain their composure and set out to hide Adam’s body in the garage, and take the money. Eve, though, seems like she still has some reservations over what happened. Walter, realizing this might prove troublesome for his plan, mocks Eve by saying she must have really enjoyed the Adam treatment. They bicker again and it becomes clear there’s just no uniting these two. Not even a maniac with a gun could do that.

The next day, on the highway, Walters gets into trouble with some teenagers, ending with the teens sabotaging the road and making the car trips. The teenagers get Walter’s pockets, but stupidly leave out the bagful of money, something Walter laughs at once he recollects his composure.

Miraculously, the temperamental man escapes uninjured while Eve seems to suffer from a broken back. Eve tearfully asks Walter to help, but Walter dismisses it easily, all the while grabbing the money and getting out of the car. Noticing the gas leaks out thanks to the accident, Walter drags Adam’s body out of the trunk and places it near Eve, giving Adam & Eve a chance to be together for the last time. With an evil intent on his eyes, Walter lights the gas and leaves as Eve is burnt alive alongside the car. The movie ends with Walter, now carrying loads of dollars, trying to hitch hike his way to Mexico.