The story is about a demon named Kick Girl who possesses the ability to unlock the seal that holds all the demons captive. Mortals wish to annihilate her or worship her, but she does not care for either of them. All she wants is to prevent the seal from being opened, which is ironic since her closest friend (and also kind of a jerk though she loves them anyway) is locked there. She joins forces with a priest who sees her as a savior, even though most in his religion would see her as a monster. Together they set out on an adventure to protect the seal, and if it opens, to stop the demons that will come out of it.
I also found a prequel that came out before the Mystery Babylon series, called Kick Girl, which takes place a thousand years before the demons were captured. I haven't been able to read it yet, and you don't need to read it to understand Mystery Babylon, because that series stands on its own.
This story has lots of biblical references, mainly from Revelations. It also mixes in angels, demons, and some post-apocalyptic future tech, mostly ruins from a thousand years ago, as most technology as depleted after the apocalypse. I found the whole thing very intriguing and the plot line kept me interested.
Please feel free to read this comic, and I hope you'll find it as enjoyable as I did!
Links
Read Mystery Babylon
Author's Website