My brother and his wife suddenly went overseas for work, so I had to look after my niece, Shioriho, while they were away. When I was reading a book of pure literature on my day off, Shioriho seemed to be interested in the story of forbidden love in the book. Since then, Shioriho has been seducing me, calling it "forbidden love". My reason collapsed due to her provocative displays and closeness, and I became the prey of my devilish niece...!