Emma's Submission (Nexus Classic)

This fourth volume of Emma's story finds its very pretty heroine back in the thrall of the sadistic Ursula, who is now supplying well-trained young women as slaves and pleasure creatures to wealthy overseas clients.
Having been trained by Sabhu - Ursula's Haitian assistant and slave-trainer - Emma is hired out to the cruel wife of an African dictiator who uses her in the most degrading ways.
Emma soon discovers that the woman has acquired a painting which has been stolen from Ursula. Ursula wants it back at any cost and if Emma fails in her mission to retieve it, she may never see her beloved mistress again