With a compelling desire to be punished, Mary (as a birthday treat to herself) contacts a Dominant she finds through a kinky magazine advertisement. She meets with "Sir" for her first dose of corporal punishment, and very soon finds herself falling under the total control of this discipline master. However, "Sir" has his own ideas with regards to Mary's future, along with his own methods of ensuring her obedience to his will. Mary becomes part of his household and her master's expanding stable of slave girls. When jealousy between slaves rears its ugly head, hard decisions need to be made, along with some painful consequences. Eventually, Mary is sent to "The College" for training, where she's placed under the strict control of a highly experienced madam and turned into a ponygirl.