Set in gold rush-era Victoria. A prospector who turns to crime and opium after failing at gold mining, Dan Morgan (Dennis Hopper) spends six brutal years in prison before terrorising country Victoria with a young Aboriginal (David Gulpilil). Having escaped into NSW, the bush ranger and his accomplice easily dodge the police and mercilessly intimidate the wealthy land owners. But wracked by madness and a lust to avenge an earlier attack from an irate squatter, the notorious Mad Dog makes a perilous journey back into Victoria.