A yakuza search for his past

In 1929 the fossil of a 500,000 year old man is discovered in China. In 1941 the Japanese army confiscates this find, but during the war the remains disappear. Based on these factual events, this movie takes off with a science fiction story involving a space rocket which places a satellite in orbit containing a secret cargo. The satellite crashes on a remote island and footprints are found in the sand leading away from the crash site. A story of how an ancient primitive cave-dwelling family contends with the scientists who want to study them.