Goshujin-sama wa Imouto Desu ka -Mkkozuki no Ore ga Nande Imouto no M Otoko ni! | ご主人様は妹ですか？ ～Ｍっ娘好きの俺が、なんで妹のＭ男に！？～

The Sazuka family's parents are on an overseas assignment. Due to his studies, "Kimiko" stayed behind with his younger sister, "Sarasa", to take care of things.

"Kimiko" is treated harshly by "Sarasa". It's not out of disgust or anything like that, but simply because "Sarasa" has been a bit of a handful since she was little, and it had become her daily routine.

In such a situation, he gradually came to prefer “well-behaved M girls,” the complete opposite of “full-figured girls,” and in case he might meet a destined M girl, he stocked up on SM-related adult goods via mail order, then one day…

"Sarasa" threw something at "Kimihiko". "What is this? What is this disgusting thing? I found it in your room!"

"Sarasa" found the merchandise.

"I'll tell Mom! That you bought something like this with your allowance!" "Th, that..." "If you don't want that, then listen to what I say."

His little sister threatened him with a faint smile....