This is one of several tie-ins to Marvel's latest event, the Secret Invasion. It's also one of the few that may be enjoyed either individually or as a tie-in.
As a result of last year's Civil War event, three of Marvel's "big brains" (Reed Richards, Tony Stark, and Hank Pym) developed a list of 100 ideas to make the world a better place. One of Hank Pym's ideas was the 50 State Initiative, which would train superheroes and place them in each of the 50 United States as established government teams. Now, thanks to the Secret Invasion, Hank Pym stands revealed as a Skrull infiltrator. The 50 State Initiative has a few secrets, and the entire country has been infiltrated by the shape-shifting and world-conquering Skrulls. With the Skrulls keeping the usual heroes occupied, it's up to the unusual, untrained, and inexperienced heroes of the Initiative to win this war.
Cowriters Dan Slott and Christos N. Gage have spent the better part of a year establishing the recruits, drawing inspiration from all sorts of interesting but unused characters from Marvel's substantial history. The writing team delivers as they always do on this title: the reader knows the necessary background for all members of a diverse cast, gets filled in on what they need to know from the main event, and is entertained the entire time. This is written as realistically as a story about shape-changing alien invaders and superhuman defenders can be. The recruits are rookies, and they don't all survive. They react to the stress differently, with reactions ranging from leading the charge to cowering in the darkest available corner. This is filled with humour and tragedy alike, and most importantly, tells a story that is interested when viewed in or out of the context of the main event.
The art teams are varied. In fact, the only negative comment I have is that the art teams rotate too often, leading to slightly jarring changes between issues. Each individual art team is good; I'd have been happy if any of the teams (of which there were at least three) had done the entire collection. The styles aren't tremendously dissimilar, but you'll know when you've gone from one to the other.
In general, "Avengers: The Initiative" has been one of the most consistently dependable titles Marvel has published where quality is concerned, and that quality is preserved here. Of all of the tie-ins I've read (and I made a point of reading all 24) this is the most enjoyable. I highly recommend it, whether you've read the main event or not; it stands on its own just as well.