I can't believe I only did a quick blurb on this issue when it first came out! - BC
First off, since this came out the same day as Final Crisis #4, rather than a month BEFORE Final Crisis #4, they really should have had something in the book saying "Read this before you read Final Crisis #4," since this book leads directly into Final Crisis #4 and Final Crisis #4 actually spoils the ending of this comic book.
Ah well, delays, can't beat 'em...that's all I got! ;)
As for this issue, in a clever move, writer Grant Morrison has been "channel surfing" throughout Final Crisis (I've been calling it pointillism, where there are a bunch of different points that combine to form one painting, but I can see Morrison's view of it as surfing through a bunch of channels to give you an idea of the sheer scope of all the information that is available to you at once), so for this one-shot, he picked one "channel" (or "point") and shows you it fully, thereby signifying "If this one channel is cool, then you can imagine that all the other channels are cool, as well, so that's how epic this crisis is."
I was not thrilled with Matthew Clark's artwork on this comic, but it sufficed, I suppose.
This was by far the most straightforward issue out of all the Final Crisis issues by Morrison, as here we have a standard enough superhero comic. The great hero, Black Lightning, is all alone in a world of brainwashed villains and heroes, and Lightning comes across the family of the Tattooed Man, and Lightning and the Tattooed Man clash with Lightning's optimism going up against the Tattooed Man's cynicism, which is poisoning the Tattooed Man's family, as well.
Lightning is on a mission to deliver a valuable piece of information, but being a hero, he can't just stand by and let the Tattooed Man and his family fall victim to the Justifiers, so he helps them, and along the way, the Tattoed Man ceases to be a real villain. As is the case for Final Crisis as a whole, optimism wins out over cynicism.
We get a great sacrifice and a sad ending, but a hopeful beginning to the next chapter in Final Crisis.
The story is a bit of a slight one, but it's strongly told and quite compelling.
And if all the other channels are as interesting as this one, then this certainly was en epic crisis.