A tied up married woman - the back of a white coat wet from bondage

Her husband Tomoyuki, her husband's younger brother Masayuki, and her wife Yumi, who has been leading the way in clinical practice, run a small hospital together... Masayuki, a nurse who is usually unreliable, and Yumi, a noble female doctor who supports the hospital... After an incident in which the two of them are in a relationship, they start to become distorted. During the day there are "the one who gives orders" and "the one who is ordered", and at night there are "the one who binds" and "the one who is bound." After realizing her hidden masochism, Yumi gradually expands her perverted desires, and forgets her guilt towards her husband and falls into bondage...