mom's armpit hair

Ken is an only son who grew up surrounded by a beautiful mother and a wealthy family. Ken was especially proud of his mother, Chinami. One day, Chinami's friend Hayashi comes to visit and accidentally learns about Chinami's armpit hair. Then, Ken is made fun of by the forest, saying that his mother has armpit hair. Ken harbors hatred for his proud mother's thick hair, which seems to betray her. However, when Ken learns that this is his father's twisted fetish, he too becomes drawn to his mysterious charm...