Being an Aussie horror, this is a little off kilter, so it's best to go with the flow rather than going in thinking you know what to expect.
A relatively tight-knit car-load of friends on a journey initially think their dull day is about to get mildly livened up by the passing of a 'road train' - a huge truck of several connected trailers used to make transporting cargo across the enormous and deserted Outback more practical. However, interest turns to horror when the vehicle batters them off the road, and then mysteriously parks up within sight of the wreckage.
Upon investigating it, they find it deserted and take it in order to get help.
At this point the psychological horror begins to kick in, as slow-burn insanity begins to plague some of the friends. Friendships tear apart, and it becomes apparent that the original crazed driver might also want his vehicle back.
It isn't played flawlessly - some of the 'friends at odds' stuff has all been done before, and some patience is needed for the scenes of the friends lost in the outback, but as long as you 'get it' and are willing to play along with the idea, it becomes enjoyably tense. There's more gore nearer the end, and the irrational behaviour starts to be a little more explainable, but it's more psych than slice.
Fun, interesting low budget slow burn horror.