The Tebricks, a charming and upstanding young couple, have moved to Oxfordshire to begin their married life, happily unaware of the future awaiting them. When Sylvia turns suddenly into a fox their fortunes are changed forever, despite all of her strenuous attempts to adhere to the proprieties of her upbringing and resist the feral instincts of her current form. Increasingly isolated in their home, Richard does all he can to protect his wife from the dangers inherent in the outside world, but these dangers soon prove impossible to fight and inevitably break down the boundaries between the newlyweds and what lies beyond the garden walls.