The premise is Janey Sinclair is the titular Gray Widow. Unlike the vast majority of female superheroes across all media, she is fully covered and wears a set of body-armor that is more akin to Boba Fett or Samus Aran than Wonder Woman's attire (not that I don't love Princess Diana of Themyscira). She is also capable of teleporting, an ability that makes her unique among humanity as far as she knows. Janey has had a series of horrible events happen to her in recent years and it has convinced her to become a crime-fighting vigilante.
Janey has some initial success with her attempts to clean up Atlanta, Georgia because she has a near preternatural sense for when crime is about to go down. She also benefits from the fact she can be at any location instantly without any need to wait for police. Her motives aren't entirely pure, though, because she's driven by a desire to vent the anger she feels from so many horrible tragedies in her life. It takes a lot to turn someone into a teleporting Batwoman and Janey has more justification than Bruce Wayne by far.
Unfortunately, Janey is not the only superpowered individual in the world. Simon Grove is blessed with the ability to shapeshift and is truly sick in the head. A violent misogynist and serial killer, he's protected by individuals who want to figure out the nature of his abilities. Indeed, people who want to exploit the powers of Augments are everywhere in Georgia and they have the resources to carry out their mission in secret. Well, at least until Janey blows the whole thing open by drawing massive amounts of attention to the fact superpowers are real.
I really enjoyed this book and think a large part of this is due to the fact Dan tries to keep both the comic book elements as well as a gritty "realistic" story. It's more or less a prose version of The Dark Knight with the addition of superpowers. Janey is a fascinating character that can't fully come to terms with her own simmering rage because she's not a naturally violent or aggressive person. The Gray Widow is something that springs from her pain and her attempts to live a normal life while also bouncing around town beating criminals is an interesting contrast. Certainly, it plays havoc with her love life.
I think my favorite part of the book is the fact that Janey unwittingly triggers a media frenzy with her actions, having never quite contemplated that the public would be interested in the sudden appearance of a real life superhero among them. She inspires imitators, lawsuit happy bottom feeders, and a public that doesn't quite realize how serious her actions are. The police, of course, are confused as much as anything else. There's also the typical media vultures who only know that the public will eat this up.
In conclusion, Gray Widow's Walk is an excellent superhero prose fiction novel and one that I very much enjoyed. I'm definitely going to check out the other two volumes in the trilogy and I'm eager to see how the story turns out. A warning for readers, Simon Grove is a femicide focused serial killer that is motivated by sick obsessions. Dan Jolley always cuts away from the horrible things the man does but it's not too hard to fill in the blanks as to what he does.