My friend's wife: "I know your wife is frustrated..."

One day, a courier arrived at Kobayashi's house. It contains adult toys that I don't remember ordering. When I checked the address, I found out that the name was Lina, the wife of a friend and wife who lives next door. Kobayashi never saw Lina with any naughty eyes, but her strange fantasies escalate. Kobayashi holds back his desire to do something and visits the Ayana family. As I expected, my friend hasn't gone home yet. Even though she doesn't know what's going to happen, Lina welcomes a hungry beast with a smile that's the same as usual...