### Clue: Made mistake in discussion before everything's gone belly up — pantomime! (10)
### Answer: CINDERELLA 
 ### Explanation: Definition: pantomime
 **Homophone of**(… in discussion) "sinned"(made mistake/committed a wrong) + ERE(before, when referring to time, as in "it was gone ere long") + **reversal of**(…'s gone belly up) ALL(everything).
… and her stepsisters.