Scott Snyder's six-issue miniseries will show the former Batgirl take a central role in the story.
"She's not just a sidekick or anything," the Vampire writer told Newsarama. "She has an emotional stake in solving the mystery that is Main core to the story.
"[Co-writer Kyle Higgins] and I are huge fans of This character, and the series with her as a part of it from the very beginning. She's not a character we threw in lightly at all, as someone to just be part of the cast for fun."
The series will explore the mysterious historical links of Cain's family with Gotham City, as well as other Families including the Waynes, the Drakes and the Cobblepots.
Cain turned down her role as Batgirl in the first issue of the current ongoing series, passing the mantle on to Stephanie Brown.
Snyder is also right now writing Detective Comics for DC. Issue #881 will mark the end of his first arc, 'Black Mirror', but would not confirm whether it would also be the end of his run on the title.