Man's name is KarekitsuneTaka. He is a home security guard who is in service for 20 years. To protect a residence, from fathers remarriage partner Katsuragi Shouko who cannot manage her corpulent body, child from previous marriage, elder sister Sayaka who deprives mans glance by a big chest and younger sister Yuki who is cheeky but has a well-balanced body. From his intuition as a house guard, he has seen through Shouko who was trying to take over the family. To protect irreplaceable home, he takes aim at Yuki, younger sister from previous marriage, he searches for her weakness by making good use of numerous voyeurist machines. The beautiful breast with a nice shape though it is small. Daily life inside groin exposed. Woman friend and dense touching that exceeds friendship. The camera captures the ecstatic expression. And home security guard who grasps the weakness, girl's initial experience is devoured greedily.