The premise is pretty much like D-Grayman and they're alike, sharing similar Victorian aesthetics, but with differences as always. The story begins after mysterious creatures named "Archons" suddenly appear in the world. Humanity faces the threat of annihilation from these creatures. Only the "Chalice," the source of humanity, can defeat the powerful Archons. So, the humans assemble an Archon-slaying unit from fighters who have the ability to bring forth the Chalice to fight. The ones chosen to fight the Archons with the Chalice as their weapon are called Goulart Knghts.
So, if you loved (and miss) D-Grayman, this is THE series to watch out for in December 25th, the date the DVD will be shipped.