The word "story" is not quite right, because in the end, this look at Batman's life, poignant and full of awe, is not a story. It doesn't have a plot to follow, at least none that you didn't already know. As we'd already seen in the first part (and the preview), we get many tales of Batman's death, and this story is not about telling us that one of them was "real". All we know is that Batman dies and before he dies he gets to say goodbye to himself. If there's a real literary inspiration for this story, it's Goodnight Moon, and as Batman says goodbye to himself, he says goodnight to Robin, and Alfred, and the Giant Penny in the Batcave, and even to the Joker, too, because all of those things are him.
By recycling all past eras of Batman at once, Gaiman gets to the heart of the character without choosing any of them. When we see the key to Superman's Fortress of Solitude, we get an entire era handed to us in one tiny geometric figure. The Betty Kane Bat-Girl hands us another, and Kubert's impeccable take on Brian Bolland's art from The Killing Joke hands us another, and it's all there -- everything that Batman ever was. Batman's life story is not a plot. It is a cycle. Villains try to take advantage of victims, Batman stands in their way, and he wins again and again.
There are three main impressions that Gaiman and Kubert try to get across, and they get them all across brilliantly. One, that Batman has a wonderfully colorful cast of characters around him, sometimes goofy and sometimes lethal and sociopathic, but always diverse, like a puzzle built to confound the world's greatest detective. Two, that Batman never gives up. People sometimes comment that Batman is more realistic than other superheroes, and it is quite rightly objected that swinging a hundred feet on a rope into a gang of armed murderers and surviving the experience is as much science fiction as any deed could be. But Batman's real superpower is not the incredible fighting prowess (which we all lack) or the incredible knowledge (which we couldn't acquire in a lifetime) or even the personalized helicopter that we can't afford. It's that he never gives up, and in our weakest moments, we can forget that it's a story and tell ourselves that we don't need to give up. And the third, perhaps most powerful part of this story -- of Batman's story -- is that it's very tragic. Five spare panels in Detective #33 told us the origin of Batman that can be read in a minute, but never really faced fully -- the horror of a little boy watching as two gunshots take his parents from him. The rest of his life is an attempt to respond to that event. He saves other lives, saves the city, and with the Justice League often saves the world, but he can never do the one thing he would so desperately wish to do -- to undo that terrible minute.
But Batman's life is not just a cycle that lasts one issue at a time. It is a longer cycle encompassing his whole life and taking him from newsprint to digital animation to the big screen. It is a cycle within which the cycle of fighting crime occupies a smaller part. When each new medium begins anew, his parents die, and he starts his war again. But he gets to be the boy who lived before the tragedy again and again. Watch 1989's Batman film, and you see the innocent, happy boy. Watch Batman Begins, and you see him again, just as he was for one panel in 1939's Detective #33. In DCU continuity, Batman has left us for a while. Somewhere, he's a little boy again and has not yet known tragedy. Somewhere, he is sitting on his mother's lap reading a book. He has not yet faced down psychopaths and become Dick Grayson's mentor. He's just a boy. He's just happy.