When Kyle Rayner first showed up, it was after the character assassination of Hal Jordan, and also he was promoted as just the best thing ever. It took a while for a lot of people to warm to him, and oddly it wasn't in his own title, it was in the pages of JLA by Grant Morrison (him, again). However, Kyle did eventually get his audience and fans, and there are plenty of people for whom he is "their" Lantern. So when Hal Jordan returned, there was plenty of fear that "their" Lantern would be pushed aside and forgotten. Well, he wasn't forgotten. At worst, the focus just shifted away from him. And now with the new 52, he's headlining his own team of other ring-bearers.
Other ring-bearers? Yeah, when Hal Jordan came back, a great big metaplot kicked off about ringwearers of other colors: red, orange, yellow, blue, indigo, and violet, each tied to a different emotion or concept. And black and white, too. There was this big war between them all, and they had to team up to defeat at least one big threat. So there are now seven kinds of lantern corps running around the universe.
And for some reason, one ring from each corps has decided to hitch themselves to Kyle.
After a brief retelling of Kyle's origin (in an alley one night, a guardian gives him a Green Lantern ring when there are no other Green Lanterns he can use, sort of the cosmic equivalent of being thrown in the deep end and told to use the nuclear missile as a flotation device), we fast forward to the modern day, and Kyle is a lesser known but still accepted Green Lantern. And one member of each of the other corps dies and their rings fly through space to choose Kyle as their new bearer.
And several members of the various corps follow, some in anger, some affronted, some just wanting answers. And so does Kyle. He goes to Oa, the headquarters planet of the Green Lanterns, and tries to ask the Guardians what's going on, while dodging or fighting back against the other corps members. The Guardians are busy lobotomizing themselves so they feel no emotions, and aren't all that interested in Kyle's current predicament. Right now, we're still not sure exactly why the rings chose Kyle, nor why, at a pivotal point in the most recent issue as of this writing, they abandoned him. It's implied that it might have to do with fan-favorite Larfleeze, the sole real member of the Orange Lanterns Corps, and the greediest being in the universe, but that might be a red herring.
Overall, this series kind of started off the weakest of the Green Lantern books. We don't really gain any insight into the various corps members who will presumably be the titular New Guardians, and we has as much clue as to what's really going on as any of the characters in the book. Which is to say, none. The third issue was the best, with bit about the Orange Lanterns, and they're always entertaining, and next issue promises more, so yeah I'm going to keep following this one. However, it still has the Guardians of the Universe as major league douchebags, and it has one member of the Green Lantern Corps lose coolness points for defending them. So there's that mark against it.
Aaron "The Mad Whitaker" Bourque; Larfleeze and the Orange Lanterns are the best part of this "spectrum of lanterns" story idea.