In all honesty this is probably the best tie in to the Battle of the Cowl tie in so far. For the most part all of the tie ins dont really tie in to the story. They seem to be one shots with the Battle of Cowl logo plastered on it. The Underground furthered the story of the battle to be supreme crime boss of Gotham along and gave us a little more information on the Black Mask. It also was a sucessfull prologue to a future story involving the Riddler and a few other females.  Even thought I personally didnt like this book I got to respect Chris Yost for writing a respectable tie in and a good prologue. Once again I have to say if any one wants to write an event pay attention to what chris yost does.