During a long holiday, brothers (older brother Ginnji and younger brother Hiroshi) and their wives Miyako and Misa gathered at their family home. Although their father-in-law Kiyoharu lived there, they had come together out of concern for his recent onset of dementia. Despite this, the couples were enjoying a leisurely holiday, but beneath the surface, each was entangled in affairs of the heart. Hiroshi had been harboring feelings for his brother's wife, Miyako, while Hiroshi's wife, Misa, was drawn to Ginnji. The couples repeated their affairs, but an unexpected action by their father-in-law exposed their relationships…
