>>2It is an alternate-universe retelling of the Code Geass story. Lelouch disappears at Shinjuku and is presumed dead by Nunnally, who travels to the ghetto and encounters an entity called Nemo, with which she makes her own Geass contract. She manifests the power to control a special type of Knightmare that embodies her suppressed anger and goes on to fight the Britannian Empire in her own way.
It is quite excellent, I think it's the best of the various Geass manga adaptations. There are many new or adapted characters that give the story a very fresh feel.