I think this is supposed to be the down under's version of FROGS, but doesn't work nearly so well as that classic Drive-in movie. What I did learn from this is to never go on a camping trip to the Australian Outback!
An extremely unlikable couple, who aren't speaking to each other, go on a weekend trip, hours away, to the Outback. On the way they are both smoking, he almost gets in an accident, and runs over a kangaroo. Once they set up camp he starts chopping down a tree for no reason, throws litter about and they spray insecticide although they've left food all around. One day he starts shooting at a dark shape in the ocean and the next day finds it washed ashore. It was a female Dugong (Sea Cow). That night they hear these awful noises, somewhat like a child's cry, and it's the Cow's pup calling for its mother. Then, at night when the man tries to pick up a small, cute opossum, it latches onto his hand and bites him, which he wasn't expecting. There's also a close call with a poisonous snake and some tarantulas. Oh, and they find a body of someone who was trapped in their car when the tide came in.
Then, things start to blur as he becomes more unstable....and his wife ends up dead, with an arrow through her neck. He drives around, gets lost and gets stuck, then finally stumbles upon a road where he's struck by a passing Truck, which ironically kills him just like he did the kangaroo at the beginning of the movie.