A Certain Family's Incest Genealogy

The Life of Kyoichi Mitsugi, a pervert who adores bondage, is the story of a young man with a perverted nature whose life changed drastically after his father's sudden remarriage.
His mother and sisters, with their arrogant demeanor and smugness, led carefree lives until one summer day when Kyoichi's frustration and desire peaked. In a fit of lust, he lashed out at his mother Mizuno and was kicked out of the house.
Since then, our protagonist spends his nights in a storage room in the garden. There he discovers a manual and various lewd devices that belonged to his grandfather, Kyorakusai.
Examining the manual, he felt a lust stirring inside him.