What the name of this drama?

I really can't remember this drama name, and I don't remember the story very good ether, but.... all i remember is : A woman that works as an agent, entered a high school under cover as a student to find a drag dealer in the school. I think it was a Korean drama.... I really hope you can help!!! (If you find any thing that may be related to this story please write it) :D Thanks!!!!

Nana87 wrote: Are you sure its not the movie She's on Duty? That's the only one that comes to mind.

Yes, i already know 'She's on duty" and i'm sure it's not it....

Nana87 wrote: ummm sorry no clue then :(

ThanX anyway, i'm glad you helped me! :)