Newly married couple Mikio and Yoshimi (Arimura Chika) have just moved into an apartment. As they are moving, the happy couple is watched by their neighbor, Mitsuru, a college student preparing to retake entrance exams. Mitsuru, who is aiming to enter medical school, places his stethoscope through the wall and listens to the sounds of Yoshimi's daily life. Mitsuru's behavior gradually escalates, and he sets up a hidden camera in Yoshimi's room and begins to monitor her daily activities. Then, one day, Yoshimi's ex-boyfriend suddenly appears...