Night Shift Nurses

Hirasaka Ryuuji works as a gynecologist in a small hospital, and at first glance is a simple man. However, underneath his mask and concealed madness is a man who lusts after women to violate their bodies and use them as experiments.

One day, he received a request to work part-time as a doctor from St. Juliana Hospital, a prestigious and well-known private hospital. There he encountered his classmate from his days as a medical student, Jinguuji Narumi.
Eight years ago, Ryuuji attacked her in a laboratory, performing experiments on her body. Ryuuji, fearing this former incident being made public, receives a surprising request from Narumi.
Four nurses of the highest quality for you to experiment with to your heart's content...although suspicious and doubtful of Narumi initally, the animal desire that raged within him once before awakens, and Ryuuji makes his decision...

[Translated from Getchu]