"The Last Wave" is one of those movies that relies heavily on the mind. The title refers to the Aboriginal doomsday theory: there will be one last wave that wipes out everything.
David Burton (Richard Chamberlain) is a Sydney lawyer hired to defend some Aborigines accused of murder. Around this time, there has been unusually heavy rainfall in Australia. While defending the Aborigines, David learns the last wave theory, and begins to wonder whether it's just mythology.
The movie's last sequence is a metaphor for descending into the depths of one's mind. Peter Weir created a perplexing, but thought-provoking, movie. Aboriginal actor David Gulpilil (whom you may have seen in "Walkabout", "Crocodile Dundee" and "Rabbit-Proof Fence") provides an interesting supporting role as one of the defendants.
If you get a chance, watch the "making of" feature on the DVD. Peter Weir explains some of the film's undertones, some of which relate to Richard Chamberlain's background.