Since the inception of the Secret Six, Catman has been the undisputed breakout star of the series. The dynamic between Deadshot and him makes the book a consistently fun, if sometimes over-the-top violent, read. In this collected TPB edition we are treated to a 4-part storyline that could be considered Thomas Blake's solo story. After his son (with Jade, the assassin who also had a child with Arsenal) is kidnapped and Jade is brutally beaten up, Blake goes over the edge to find the child.
This is not your typical father-in-distress story, however, because Catman isn't a typical dad. Rather than negotiate with the kidnappers to keep his son alive, he immediately considers the child dead and instead threatens the kidnappers with the simple promise "In the dark, I will find you." No negotiations, just the understanding that they have made a mistake that will cost them their lives. From there, Blake tracks them all over the globe, killing the kidnappers one by one before returning home to find the man responsible and deal with him. You thought Liam Neeson was tough in "Taken"? Catman makes him look like an amateur.
The key to Catman's appeal in this book is summed up by Deadshot early on. "He's never crossed that line the rest of us have crossed. He's never gone to that point of no return." It's as if to say there was something in Catman that allowed the potential of him becoming another Batman or something. In this storyline, however, he shocks his teammates (not easy to do when you're talking about guys like Bane and Deadshot!) and the reader with his complete and total brutality in dealing with the kidnappers. As such, this is an incredibly violent storyline that is not for the faint of heart. For instance, one of the men is dispatched by Blake literally biting the man's face off.
The point of the story is to show how this quiet storm of the team has the potential to actually be the most brutal killer of all. In the end there is one final redemptive act Blake does for his son that gives us a hope that perhaps there could still be a hero in there somewhere. The final two stories of the TPB are solo shots of the Secret Six kidnapped to an island where superpowered hunters plan to kill them (it doesn't go well for the hunters), and a single shot alternate universe type story of the team in the old west. I have no idea what that story has to do with anything, but it makes for an interesting distraction to see Deadshot as an actual gunfighter.
The Secret Six series is a hit-and-miss affair, but the 4-part story collected here is, to me, the highlight of the series so far.