Married women who became aware of marital sex swapping

Mr. and Mrs. Kimura (husband, Seiji, wife, Aika) are worried about getting stuck in a sex rut. Seiji, who always fails at critical points, consults his subordinate Ryo for advice. ``We need to come up with something.'' Ryo immediately invited Seiji to dinner. When Ryo gets drunk and falls asleep, Seiji pushes down on his wife, Yu, who has an outstanding style. His son, who usually doesn't listen to what he says, is binging for some reason! Seiji gets a hint on how to get out of his sexual rut and invites Aika to a weekend party...