Derek and Kate were held hostage by rogue prisoners.
Unbeknownst to the prison’s director, the head guard was hosting a fight club that involved corrections officers betting on which inmate would win. After numerous prisoners sought revenge by killing the guards, the BAU was called in and found the culprit. In an effort to keep his secret, the unsub (“unknown subject”) released all the prisoners and, instead, trapped Callahan and Morgan at knifepoint.
Watch Criminal Minds Wednesdays at 9/8c on CBS.