Incest [silent] Incest - my dad is next to me...

The Murakami family on a holiday. What my father, Koichi, sees is the usual, ordinary lunch scene. However, an extraordinary act was being carried out in a place that Koichi couldn't see. It is an incest between a mother and son that is never allowed. The mother, who has a sense of immorality, stops her son, but as if to enjoy the thrill, her actions gradually escalate.