After her fiancé leaves her for his mistress and Sumire is demoted at work, she stumbles across a young injured homeless man in a box outside her condominium. She takes him in and becomes attached to him. As a joke, she says she wants to keep him as a pet. To her surprise, the young man agrees. She names him , after her beloved dog from childhood. Sumire provides room and board, and Momo provides unconditional love and loyalty. Sumire says there is no sex in their relationship, and she will only sleep with men who have the "three highs": higher pay, higher education and higher height (i.e. taller than her 170 cm.) Despite this, there is definite sexual tension in their relationship.