Mekurumeku Buai no Utage

Chika Osanai is a 28 year old woman who has been happily married for the past 2 years. She met her husband when they both were studying to become junior high school teachers at the university. Since her husband was six year her senior he graduated before Chika could finish her studies and they moved to the city where he got a job and she became a housewife. With their savings they have now moved into an apartment in a high-rise building.

Chika befriending the neighboring woman Mariko who, like Chika is also a housewife. Mariko Kurihara is 33 years old and her husband is rarely home since he is an airplane captain and do a lot of travel. All seems calm and quiet in the new building until one day when Chika is over for tea at Mariko’s apartment and there is a sudden ring at the door. In comes and handsome young man who introduces himself as Miura. The next moment he orders Mariko to kiss him and Chika is suddenly witnessing an act of infidelity for the first time. At first she is distraught be the scene, but as time goes on she finds herself more and more drawn to the experience. Then one day when Chika is going around town doing some shopping she sees Miura and an unexpected fire begins to burn inside her. She tries to convince herself it is all a dream, but things soon become very real.

[From EroEroReview]