In the Principality of Pasatafa ruled by an Autocracy, a character must undergo a Trial by combat.
He has been framed by A monster or group of monsters - mind flayers, a beholder, giants, a dragon - and if found guilty of Counterfeiting, his punishment will be Wall of Force. The perfect barrier combined with Permanency assuming the other surfaces of the cell are secure. Put a curtain across when you get tired of watching the prisoner make rude gestures at you.

Principality - The feudatory land, or state, ruled by a prince (monarch, technically), often ranking equally high as the duke.
Autocracy - Government by a single person having unlimited power; despotism.
Trial by combat - Fight to the death, winner is innocent