A miscarriage of justice primarily is the conviction and punishment of a person for a crime they did not commit. The term can also apply to errors in the other direction—"errors of impunity", and to civil cases. Most criminal justice systems have some means to overturn, or "quash", a wrongful conviction, but this is often difficult to achieve. The most serious instances occur when a wrongful conviction is not overturned for several years, or until after the innocent person has been executed or died in jail.

The ninth season of premiered on CBS on October 9, 2008 and ended May 14, 2009.