Not Your Average Angel Story
This is one of those rare examples where a hero other than Batman and/or Superman was granted an Elseworlds story that wasn't simply an annual or used as a type of sequel for something else. Heck, even Wonder Woman and Green Lantern only got two.
The basic story is a retelling of Peter David's first half of the last Supergirl series, the "Earth-Angel" saga. Matrix is now literally an angel, one of many whose task is to save those teetering on the brink of damnation, the Amenlee. Her compatriot is Zauriel, part of those who work with human souls before they are born, the Kindel. Matrix is expressing doubts about her latest charge, a girl named Linda Danvers who is resisting her every attempt at helping her. One of the reoccurring themes of this story is the idea of love and liking. Matrix and Zauriel are SUPPOSED to love humans, they don't actually have a choice in the matter. But Zauriel admits that he actually likes them beyond what his role is supposed to be, yet Matrix keeps expressing more and more doubts on whether or not she has the capacity to do so, along with the doubt that Linda can truly be saved. When you think about it, people always talk about guardian angels, yet we have to wonder if they actually love us because they choose to, or because that's what they are there for. Growing to love and like something, and being born to love something are two entirely different things.
In all of this there is Matrix's charge, Linda Danvers, who is supposedly very self-willed towards the dark side. Although we never actually see Linda committing any sins so we just go on Matrix's judgement, as well as the Spectre's, who attempts to claim Linda twice in the story. Linda's boyfriend, Buzz, is believed to be one of the guiding reasons behind Linda's sins, but as Buzz points out, everything she did was of her own free will. We're even told that Linda's original guardian angel "went down in flames, so to speak". However, Linda comes along quicker in her revelation than Matrix, which would be easier to assume, as Linda is not forced to conform to the ideas and life that Matrix was born for. Linda winds up being the one to save Matrix in a moment where she shows the most strength out of everyone in the story.
Beyond love there is also change, as Matrix keeps trying to resist her doubts and free will and longing for the days when she was just an extension of God's will, but every time she is nearly assimilated with another form of God and about to lose her identity she resists at the last minute. Whether she likes it or not, she's changing, and with those changes her newfound anger at Linda, and later the human race, continues to grow. At one point Matrix "possesses" Linda, and is disgusted at the so-called cage that is humanity. She is disgusted by the five senses and the bacteria and disease in a person's body. "They're dying from the moment they're born!" In a moment when Matrix, still in Linda, begins to make out with Buzz, Matrix becomes so repulsed after nearly enjoying it that she stops in the middle and almost kills Buzz with a lamp.
Matrix is constantly shown different perspectives on the human race beyond what her angelic existence knows, with help from others such as Zauriel and the Phantom Stranger. There are angelic re-imaginings of Superman, Swamp Thing, and Aquaman present in this story. Superman appears, first as the husband of a happily-married couple with two children in Kansas, and later we learn that he is an angel who is actually living among humanity without having gave up his abilities. Swamp Thing and Aquaman appear as reflections of God based on the Earth and the oceans, the Deva of the Trees and Ceetka, respectively. There role demonstrates an attempt at blending together the idea of sprites and nature spirits with ideas of God and angels, as angels themselves can be seen as counterparts to nymphs and fairies in certain other religions. An interesting note to point out is that no religion is actually identified in this book, although people would assume that because it deals with angels it's more attuned to a monotheistic religion. God is never referred to as "him" or "her", but "Hir", bringing on the idea that God is genderless, or rather, our personal idea of God differs amongst each person. We're also introduced to Buzz as a demon named M'yaa, who also appears as the Devil in a Batman-esque depiction in the final moments before Matrix nearly caves in.
Most people are always criticizing the Earth-Angel story, but in my opinion it's much more enjoyable than the whole "bad girl emo" shpeel we had to deal with for the first two or three years of the current Supergirl series.
Yes, there were a couple of things I found about the ending that were hokey, such as the scene of all the secondary characters gathering, and smiling, during the moment of big truth, and when Matrix/Linda sports her new appearance with the blank shield on Matrix's outfit now sporting an "S", even though there's no actual reason for it. But I was willing to overlook it due to the fact that someone was willing to do a Supergirl (not Superman or Superboy) Elseworlds that didn't put her in the future or just recast her into another timeline, but took the less-then-popular "Earth-Angel" storyline and reworked it into a struggle of good versus evil where the proponent of good is the one who is more likely to fall than the girl she is trying to save. In regular comics, it was up to Matrix to save Linda's soul, here, it becomes the other way around.