EDIT: I forgot the library. Omg, how could I forget the library?

I've just finished creating a rough setting map for a game like these I want to program. (Check them out, they're fun.)
Now, the problem is, I'm having trouble thinking of a good story for it. Which is why I need your help.
I don't want a super-detailed story, just a rough guideline to which we can add to, something like "Find the magical amulet to kick a**".

The setting is a Magical Academy with three floors, a basement and if needed an attic (I don't know what to place there yet.) There's also an outside part.
The ground floor obviously has an entrance hall, the cafeteria and the kitchen, an exam room, the teacher's room and the principla's office.
The second floor has all the different kinds of classroom and the library.
The third floor has the sudent's and teacher's dormitories.
The school grounds have a forest, gardens with flowers as well as vegetables, greenhouses and a lake, and possibly mountains or hills.
The basement has store rooms.
The map can always be altered.