From MangaHelpers:
It was supposed to be a memorable and exciting vacation with his girlfriend and 4 of his close college friends. Shouichi just wanted to have fun and learn the meaning of what it means to be "manly." Once they got to the hotel, the fun and drinking began. During the late hours of the night, they hear the scream of a woman coming from the parking lot. Next thing they know, Shouichi's friend "Ken" is nailed to the ceiling with his face completely punctured. The remaining people from this young group will need to figure out how to survive against this alien organism.