More Cassandra origins! Sure, it's kinda sorta thematically the same, but what do you want? She got erased! But for real... has anyone complained about this version of Cass? Because that sure would be stupid for multiple reasons.
The Spoilers:Cassandra returns to an old radioactive (or something) diamond mine that Mother used for her nursery, and through the flashbacks, she finally makes it back to where all the children lived in hopes of rescuing them. Unfortunately, Cassandra's father David is waiting for her, having slain all the children, and then does some bad guy speech and shit. Turns out Mother is going for a new, darker plan, so she's got to wipe the slate clean.
David blames Cassandra for all this, if she hadn't gone rogue and gone to "him," (Batman) then all would be well with Mother and the children would be alive. FLASHBACK! Cass found Batman some time during Endgame to inform him about Mother. It was here where he gave the drive to Cass to give to Dick if he doesn't make it, they share a moment as Batman calls her a hero.
Back to the Nursery, Cass and David begin to fight, Harper and Dick show up, Mother appears via hologram and goes "I'm gonna nuke the place, BYEZ LOLOLOLZ"