Boku no Elf Onee-san / 僕のエルフお姉さん

A world unlimitedly similar to the present age.
However, this world was a world that coexists with intellectual life forms different from humans, called "elves".
When has elves evolved from when and when they differ from humans -
Why elves and humans, two intellectual life forms were born simultaneously -
The study to explore the mystery was called "elf study".
The hero, father of Takumi Kirihara, Ryutaro Kirihara is a leading expert on the research of science at university.
For this reason, the Kirihara family lives together with a woman elf.
Her name is Sophia, Ardis, Fairgrin.
In order to cooperate with the research on the human side by Sofia's father's proposal
Special seminar lecturer at Ryutaro's seminar, she is also enrolled in the university as a research subject sample.
Takuma and Sophia grew up together since childhood and have been friends like sister and brother -
As they grew, they began to become conscious of each other as heterosexual.
Two people who are living alone.
One day, Rytaro is away from home for several days.
Both men and women who are two people check each other's feelings and they are finally tied as lovers.
Takuma and Sophia at the culmination of happiness.
...... But the dark shields creeping up on them.
A story tearing apart of loving lovers was trying to raise the curtains seriously.
Maybe you will like this game pretty warrior may cry.