Inheritance features three of the old guard superheroes and three of the new guard teaming up together to work a case. Batman (Bruce Wayne), Green Arrow (Oliver 'Ollie' Queen), and Aquaman (Arthur Curry) make up the old guard, with Nightwing (Dick Grayson), Arsenal (Roy Harper), and Tempest (Garth) as the new guard.
This is a great introduction point to several of these characters. I'm familiar with Batman and Nightwing, not as familiar with Arsenal and Green Arrow, and had only a passing familiarity with Aquaman and Tempest. The book packs a lot of good information into the storyline, and serves to introduce you to all six characters, who they are individually, and how they relate to each other. It focuses more on Nightwing, Arsenal, and Tempest than on Batman, Green Arrow, and Aquaman.
I finished reading the book several weeks ago, and while it started slow and was somewhat difficult to get into, I really enjoyed it. Devin's writing style in terms of a book is not one I tend to favor. She uses third-person omniscient, and I prefer third-person limited. I'm so used to reading third-person limited that it was somewhat difficult to adapt to omnisicent. I'd be firmly rooted inside one character's thoughts and she'd shift to another one. The head-hopping was a little jarring at first, but as the book progressed and I got used to the style, it became less of an obstacle.
Devin does a good job telling you who these people are, as the book walks you through all three old guard heroes as lousy parent/guardians to their former sidekicks, and how the sidekicks are dealing with that. Dick has issues with Bruce, Roy has issues with Ollie, and Garth has issues with Arthur, and all of these issues are distinct to them, but the themes are similar. A part of the working together arrangement is to focus on what these issues are, and how the characters are handling or not handling them. There is a ton of daddy/mentor angst, and that's like catnip for me.
She did great work on character development, and the book left me wanting to become more familiar with Arsenal, Green Arrow, Aquaman, and Tempest. Yeah, Devin gave me a jones for Aquaman. And it's Devin, so the subtext is sometimes suffocating and always there. Ollie textually hits on Dick constantly, and every time had me cracking up. Like the time he watches Dick move away, and he's in the dirty old man place, thinking about how nice the view is, and how he can understand why Batman...*hee* At several points the characters all but come right out and say Batman and Nightwing had a sexual relationship while Nightwing was Robin. Ollie calls Dick pet names and thinks to himself that there's no way Dick ever spends a night alone, and it's repeated over and over throughout the book. All. The. Time. This is also catnip for me, although not so much the Ollie angle.
The subtext between Bruce and Dick is incredibly intense. There is so much weight in whatever happens between them, and everybody around them feels it. This contrasts nicely with Arthur and Garth, who have this huge gap between them that feels old and familiar to both of them. Ollie is oblivious, and Roy is angry at him.
You get a lot of good backstory, some of which I was familiar with and some was relatively new to me. It's really tough to decide who inflicted the most damage on their sidekick. Ollie was never physically there, Arthur was emotionally unavailable, and Bruce was... Bruce. He's all of the above with a whole lot more Batfamily-specific dysfunction.
While the character relationships and dynamics are not billed as the central focus, they dominate the story and are, to me, far more interesting than the central plot. That plot focuses on Cheshire and Deathstroke, and the assassination attempt of a Qurac (fictional nation) prince while he and his family are in Gotham. As stories go, this was solid and had some interesting twists. It made a good background for the character interactions.
It's a good book, and a nice gateway into the DC universe, if you're looking for a starting point. If you're familiar, it remains enjoyable and offers some interesting insights into these characters and consequences for the decisions these mentors made in regard to their wards. It's a good read, I recommend picking it up.