Yuriko lost her husband five years ago in a dam construction collapse accident. Yuriko, consumed by grief, ended up having a physical relationship with her son Taiichi. Since then, Yuriko and Taiichi have been a mother and son who have sex all the time. Nevertheless, on the anniversary of the accident, she still offers flowers at the dam. If her husband knew that she had crossed the line with Taiichi… She couldn't end her relationship with Taiichi despite feeling guilty...
