This graphic novel supplies the back story of the Cylon "Six" from the re-imagined BATTLESTAR GALACTICA series. We're first introduced to "Rebeka", who works in a space mine on the planet Troy. Then, there's an identical woman, "Eve", being kept in a mental institution, who has no recollection of her memory. She likes putting together puzzles and has a violent streak. She eventually escapes and reveals who she is to a human she becomes close to, that she's a Cylon. He tells her she isn't a machine and she corrects him-"Cylon. Not machine". When Rebeka is killed while working she awakens in a regeneration chamber is is greeted by the five other human Cylons. And there's another version, Mary, who feels unfulfilled in her life and jumps ship, holding an anchor, drowning herself. She also wakes up in a regeneration chamber and is greeted by another Six, the mirror-image of herself. Their experience in these lives is making them more human. Eventually Eve is also killed-and comes back, only to learn her true purpose and who she is-and that she's the Cylon who meets Gaius Baltar on Caprica.
This story fits well with the continuity. It's unnecessary but interesting.