Yuika, a new nurse at a hospital, is a bit clumsy and worries about whether she can handle the job. However, thanks to the help of her sometimes gentle, sometimes strict head nurse, Yui, she is able to throw herself into her work. One day, Yuika is assigned to work the night shift with Yui. During a short break, Yuika indulges in masturbation to quell her sexual frustration. However, she is unaware that Yui is watching her with predatory eyes. That night, the women drive Yuika to madness…