This is probably one of the best origin stories I've ever read. My rating is actually 4.5 for the story, but I'm rounding it up to a 5 because of the lovely art.
Harleen, it's a new origin story of the infamous Harley Quinn. Despite following the same narrative thread of the traditional story we are all acquainted with, it provides a fresh, psychologically deeper take on how Harley went from being an ordinary if enthusiastic, psychologist to the deranged girlfriend of the Joker.
My only objection is that in the end, it felt like there was a bit of an unrealistic character change in Harley. Sure, she had been slowly descending into the Joker's trap, but just because she unwittingly killed a man, she wouldn't just become an unhinged psycho killer from that point on.
The problem, I think, is that the author wanted to write realistic characters that, to begin with, have always been portrayed ridiculously. Harley's character change is wholly attributed to a combination of her commitment to her research, her obsession with the Joker, and the Joker's masterminding abilities, which make for a fascinating read but ultimately, in my opinion, fail to properly account for her huge change of morals and personality that propels her into a life of neverending unhinged crimes.