Desperate by Jurgen von Stuka
After a small Swiss bank is robbed, four American tourists fall into a criminal trap managed by Swiss and German local and state police. Spirited out of Munich, they are taken to a secure location: an old German castle in the Alps where The Consortium trains and manages a global slave and pony network. The clueless Gus and Bill are sure this is just a huge misunderstanding that will be eventually straightened out. However, when they are abruptly stripped, interrogated and thrown into dank prison cells by their uncompromising female 'keepers', they soon realize otherwise.
The two men are slowly and painfully transformed, not just into slaves, but into submissive females slaves. Their girlfriends are similarly pierced, ringed, plugged and trained for a lives as ponygirls. After months of punishment and pain, the entire foursome eventually becomes a human pony team, pulling carriages over the frozen mountain roads and providing sexual services as needed to the organization's many clients and members.
Additional new recruits are abducted from the United States and sent to the Consortium's trainings centers. Most are young, attractive, Anglo females that are shipped east to meet increased demands for new submissive slaves. Their route from a luxury lifestyle in the USA to one of barely survivable slavery in the cages, cells and pits of the Schloss is chronicled in chilling detail, including body transformations and elaborate fetish costumes. Their sadistic captors have few restraints in the treatment of their acquisitions. Among the unlucky souls to find themselves in such dire circumstances is Eddie, a male businessman from the states, now a transsexual, who is sold to an Arab, then periodically returned for "upgrades" in her sexual repertoire. And Rene, the young female bank manager, originally a participant in the kidnap plot, is also abducted by the same cabal that trades in pony slaves. She's been selected to be a personal slave to Atella, the dominant mastermind of the plot.
Strong nonconsensual BDSM content. Includes female and male domination, male and female submissives, male to female transformation, extreme pony training, imprisonment, sexual torture, dildos, leather, latex and elaborate costuming, whipping, milking, lesbian sex, extreme sadism, sex, rope and chain bondage, extensive body piercing and rubber encapsulation.