School put me on Administrative Leave, What can I do?

I’m in SC, on administrative leave (leave with pay & benefits), for a shadowy allegation that they won’t disclose. I have a feeling about what it is, and if I’m right, I should get off scot-free.
However, someone in my school with much influence has it in for me, and I’m rather worried about what’s going on behind closed doors.
The timeline is this: They put me on Admin. Leave, they investigate, they bring me in and dump all they found and the allegations on me, and THEN give me a chance right then to defend myself.
I have a feeling I’ll be put on the spot. Is there any way I can force them to tell me what they’re investigating, so I can get a lawyer and prepare?