Even after he’s been exposed to the world as Batman, Bruce Wayne keeps his vow to avenge his parents’ death by fighting for justice. He refuses to execute his enemies, believing that once he crosses that line, he’s no better than the cowards he battles.
Though killed by Superman, The Joker continues to haunt the lives of all those touched by his madness. By destroying Metropolis, he set the events in motion which made enemies of Superman and Batman. If he were alive to see the chaos he’d created, he would surely be smiling.
Since the fall of the Regime, Harley Quinn has found little solace in the incarceration of Superman. Still feeling a tremendous void left by Joker's death, Harley remains an unstable and uneasy ally. Resolute in her conviction, she refuses to let fugitives, assassins, or even criminals she once called friends stand in the way of her exacting revenge upon the man who silenced The Joker’s laugh.