Kenichi, the only son who has been carefully raised by his mother, Reiko. His father, Ryuji, treated Kenichi sternly and told Reiko not to spoil him. However, Ryuji also spoiled Reiko like a child and enjoyed her growth by growing hair on Reiko's armpits. One day, Kenichi discovers the secret pleasure. Kenichi is jealous of Ryuji who enjoys it in the shameful part of his mother who he does not know. After seeing Reiko with a happy expression, Kenichi wants to make Reiko her own ...
