Storyarc Explained: Infinite Crisis
The hottest storyline out there these days is DC Comics' Infinite Crisis storyarc. It's quality storytelling, but can be a bit intimidating to those who haven't followed it from the start. Following is a brief explanation of what has happened so far, taken primarily from numerous Wikipedia articles. I'm trying to make this as simple as possible...not an easy task, I assure you, so please bear with me:
Infinite Crisis is a sequel to the successful 1985 mini-series Crisis on Infinite Earths. In Crisis on Infinite Earths, DC tried once and for all to consolidate all the different Multiverses within the DC Universe into a single universe.
In DC Comics, the Multiverse is a continuity construct in which multiple fictional versions of the universe exist in the same space, separated from each other by their vibrational resonances. Each universe in this Multiverse varies from the others, in either subtle or profound ways. In particular, the Earth of each universe has a different set of superheroes, or the life histories of its superheroes are different from those of others'. In several cases, characters from other publishers acquired by DC - previously established with a fictional universe of their own - have been assigned their own alternate universe within the Multiverse. For instance, the super-heroes most people are aware of today came from Earth-One. The golden age version of these heroes (in other words, the Batman, Superman, Flash, etc. as they were originally conceived in the 1930s and 1940s) were still around, but they lived on Earth-Two.
Naturally, people were having a tough time keeping all this straight, so DC created the Crisis on Infinite Earths storyline to solve the problem.
The Crisis series highlighted the efforts of nearly every DC Comics' superhero to stop the annihilation of untold numbers of alternate Earths by the super-villain Anti-Monitor. The heroes managed to save the last five parallel Earths (the homes of the known DC Universe), with the result being the creation of a single universe. The superheroes returned to a present-day reality where the various elements of the five Earths were fused into one - which defaulted into Earth-One.
Now that you have the background, we can start covering the current storyline, Infinite Crisis:
Without going into specifics, the heroes of Earth-One are having a tough time fighting the good fight. Things are getting out of hand, and in response, the Superman of Earth-Two breaks out of the world in which he departed to at the end of Crisis on Infinite Earths, accompanied by Earth-Two's Lois Lane, Superboy of Earth-Prime, and Alexander Luthor of Earth-Three. Upon his return, Superman declares his plans and intentions���?�to reverse the decision made during the Crisis on Infinite Earths to save Earth-One, and make Earth-Two the dominant and primary Earth again.
Phew! Did you manage to follow most of that? For a full explanation of the Infinite Crisis, check out the Infinite Crisis article on Wikipedia.