The story is basically about a girl who wants ot have a huge number (100) sex partners. She picks one fairly normal slob to be the one who starts things off. She end up having more real feelings for the guy.
Its a familiar romantic comedy set in a high school with the added flavour of the girl being the pervert instead of a male lead. Her delusions are voiced by a little mini version of her on a loud that floats in to tells about stuff.
Normal I'd consider this a pure fanservice anime and thus a waste of time, but for some odd reason I'm actually enjoying the humor this time around so I'd say its watchable, but not worth keeping once its had its run.