Sean Murphy's Batman: White Knight is flipping the Dark Knight's mythos on its head, painting Batman as a crazed villain and Jack Napier as a reformed Joker trying to return Gotham City to its glory days. Napier, apparently cured of his Clown Prince of Crime persona, is on a mission, not just to right his wrongs, but to rid the city of the darkness that Batman's vigilantism has brought.
Two issues in, Murphy, who's writing and drawing the series, smartly plays on the concept of the "white knight," reminding fans of that iconic line Aaron Eckhart used as Harvey Dent in Christoper Nolan's The Dark Knight. Similarly, Murphy isn't going about his hero's journey by brute force, but in a cerebral fashion and by the books, for the most part. After a near-fatal encounter with the Bat, Joker reevaluates his life in prison and emerges as a clean and sane Napier. He's now hellbent on social and political justice, but he also realizes he has to plug that gap in his heart and make amends with his soulmate.
Ergo, Napier goes to Harley Quinn, asking her to follow his newfound path. However, Murphy throws a big twist in when Napier proposes to Harley in Issue #2 and she rebuffs him, citing a need to keep Gotham's wheel of chaos turning. As this Harley chastises him for going soft, she's knocked out by another Harley, who's revealed as Harleen Quinzel, the original who's back and ready to embrace the light with her puddin'. As she reveals more of their past, we see that she isn't just the moral compass of the story, but Quinzel is the one person who knows both Batman and Joker well enough to tell us who's truly the villain and hero at the end of the day.
Murphy has positioned Quinzel as the litmus test to determine the true character of both men because she has seen them at their best and also at their worst, witnessing their evolution and their regression with a front-row seat. Murphy, recognizing that she's now in a role of more substance than style, further shakes up her status quo with Joker, not just with a sex scene or a proposal, but by reestablishing their original dynamic -- Quinzel as a therapist trying to help Napier find his purpose and true calling in this world.