Pact with a Witch

Your roommate and best friend tries to fuck Neus, the most introverted of the whole design school, who bites him just after you save her.
You discover that bite was not only for self-defense, it also contains a bewitching that turns your room.
Who everyday that pases, she seems forgeting more his past and becoming more attracted to you.
To save your friend, you make a pact wit Neus to have 4 dates, and the last night she promises to return his original form to your buddy.
There is sinister things she had not told you. Popular game oniki's kinky world.