The book opens with the investigation of a child abduction case by Marcus Driver and his soon to be late partner, Charlie Fields. They find themselves running headlong in to Mr. Freeze instead of their chosen target and Charlie ends up dead. This sets up the full fledged hunt for Mr. Freeze by both the Major Crimes Unit's dayshift (as written by Greg Rucka) and the night shift (as written by Ed Brubaker). Both groups are lovingly brought to life by Michael Lark: the artist born to draw this book. Lark's style is very down to earth as fans of his previous work in Terminal City and Scene of the Crime are aware. He brings the characters to life with his style. The major problem with this first two issue arc is the shear number of characters. We're introduced to at least 12 characters with only 4 of them (Bock, Renee Montoya, Commisioner Akins, and former Superman supporting cast member Maggie Sawyer) being known. We're basically forced in to figuring out who all these people are on the fly, which makes remembering who everyone is a pain in the ass quite a lot of the time. The addition of Batman in to the book in issue two as well as an appearance by James Gordon just clutters the opening arc up even more. I know they wanted to get all the introductions out of the way, but I really think they could have done a lot more by keeping the focus on a few fewer characters and than introduce the rest of the cast over the next couple of arcs would have made a lot more sense.
Ed Brubaker flies solo for the next arc, "Motive", as we focus on Driver's quest to find the killer of the girl he and his partner were searchign for and the beginning of issue one. He's paired with Romy Chandler, a female cop who usually partners with one of several carbon copy cops we don't know anything about yet, Nate Patton. Meanwhile, Jackson Davies, another night shift cop is assigned to track down Firebug, a criminal who hasn't been seen in several months. Driver and Chandler take over the main portion of the story, and Brubaker's writing quickly takes on the feeling of Homicide right down to the white board with red and black marker. As they continue to search for the murderer of the fourteen year old girl, Davies uses a tip from former detective Harvey Bullock (who for some reason we never see...) to track down Firebug, only to learn that they aren't quite on the right track on that case either. Finally, Driver comes to the realization that the cases might not be as seperate as they though, which leads to the stories well-written end, which again invokes Homicide with its interview in the Box.
I enjoyed this collection quite a bit, although I think the series doesn't quite live up to its hype. It's quite fascinating to see how a police procedural plays out in Batman's world, and the book is far more down to earth to the similar themed Top 10. But my biggest problem with the series is that after 5 issues, I've only really gotten to know 2 officers, Driver and Chandler, and really only one of them well (Driver). I'm sure as the series progresses more officers will get the focus, with the more familiar characters like Montoya and Sawyer taking over for Rucka's arc (especially considering Rucka's love for Renee Montoya).
As a concept however, I think Gotham Central would make a really good campaign. The idea of low powered police officers as the stars of a campaign in a low-powered superhero setting could make for a fun game. Unfortunately, I don't think this collection alone would hold enough ideas. Thankfully, there's a continuing series still going, one that I may just pick up after this TPB. In the Line of Duty is an excellent start to the series, and with the talented team behind it, I could definitely see it only getting better.

