A Japanese-American co-production involving Richard Boone as an over-the-hill big game out for one last thrill, to hunt and kill a Tyrannosaurus Rex in a recently discovered lost world beyond the arctic. It features mostly American actors although there's the odd Japanese one (mostly playing the cavemen for some reason) with special effects, dinosaur costumes and miniature work done by the Japanese company Tsuburaya Productions (famous for its work on the Ultraman series). The Trannosaurus costume in particular was a refurbished suit from Tsuburaya's earlier Dinosaur War Izenborg.