Because American soldier-of-fortune Richard Grant is falsely accused in the murder of an Indian nobleman, he disguises himself as an Arab goes to sub Saharan Africa in search of a valuable diamond field. Along the way he meets beautiful Muriel Armitage and searches for her missing brother, Tom, supposedly murdered by the seductive femme fatale Mrs. LaSalle, who's murdered herself. An ocean liner carrying all the principals and the villainous big game hunter Harris catches fire and founders although his cargo of deadly big cats escape to the mainland. Harris is aided by Mustapha, his sinister Arab accomplice and Bimi the Ape Man, a ghastly missing link who obeys his evil master's every command.