"Rogues' Reign" part four! An out-of-control Flash must figure out a way to harness his powers, because he's about to face the villain who flipped his world upside down- Mirror Master! Our hero has only one hope of survival-the Rogues are warring with each other and their forces are split. But while Barry struggles with his own abilities, are the Rogues headed for a reconciliation that would make stopping any of them that much harder?