Stephen Smith falls in love assuming that this is where happiness lies. The object of his desire is Mina Savage, the illegitimate child of parents themselves both illegitimate, a young woman whose ambitions and appetites outstrip Stephen's wildest fantasies. They become lovers. But when Mina continues to disappear at night, Stephen tries to force her to be faithful to him. Is Mina simply unfashionably promiscuous or is there something more sinister about her vampiric attitude towards other men?