The beautiful Jenny Seagrove stars with Christopher Lee and Patrick MacNee in this new mystery which once again compels Holmes to end his retirement. Far from 221B Baker Street, Holmes' classic investigation turns into an unforgettable adventure when he is called to transport the world's most valuable diamond from Africa to London! Claude Akins and Richard Todd also join in this adventure where the heat of the African jungle breeds romance, deception and murder. Filmed on location in Africa and Luxembourg.