This is a comedy adventure based on a story by Jules Verne, set in 1912, West Africa.
Diamond tycoon Kramer (Harry Andrews) has created an empire, complete with his own militia. While his daughter Erica (Ursula Andress) and the American geologist Dan Rockland (George Segal) are celebrating their engagement someone steals Kramer’s prized diamond, the Southern Star. The prime suspect is Matakit, Dan’s African helper. So he flees the scene. However, Dan and Erica believe he’s innocent and chase after him. In the meantime, Kramer’s militia commander thinks he’s guilty. So he also goes after him, but it’s because he wants the diamond for himself.