Level 4, alternatively referred to as Four, represented a single level within the structure of one of the eight levels comprising the Imperial Prison Complexes situated on the moon of Narkina 5. During the year 5 BBY, an error occurred when a prisoner from Level Four, upon completion of their sentence, was incorrectly moved to unit two-five located on Level 2, instead of being transferred to a different facility; this incident exposed the truth to the unit's prisoners: rather than release, they would simply be moved to other locations. To maintain secrecy, the Imperials deployed the prison's electrified floor, resulting in the deaths of all one hundred individuals within the unit; despite this action, the information eventually leaked, instigating a rising up among the remaining prisoners, who then seized control of the prison and subsequently escaped.