WHAT?! Sisterhood was filled with about 10,000 plot holes and unanswered questions.
Why was Maddie evil? She wasn't evil the last time we saw her. She hasn't been evil since she got possessed by demonic energy back in Inferno. That junk was out of her system by the time she came back in the 90's and started hanging out with Nate.
Why did Maddie know magic again? Again, that hasn't been a part of her since Inferno.
How did she come back?
How did she know that Logan kept a lock of Jean's hair?
How did the spell used to locate Jean's body lead them to Westchester? Jean's body isn't even on Earth anymore.
Why did Maddie need to cast a spell to locate Jean? Upon partially returning from the dead, she didn't think to look for the X-Men in Westchester and happen to see the graveyard with Jean's huge grave marker?
How did Maddie find Psylocke?
How did Cyclops know that Maddie was just a ghost, invaded their Marin base just to get Jean's hair from Logan's room, and that she was using it to find Jean's body in Westchester?
When the Sisterhood attacked, how did Cyclops know that they were attacked by Betsy back in her old body and not a resurrected Kwannon?
Why exactly did Maddie form the Hellfire Cult and get them to attack mutant kids in the streets of San Francisco if her only immediate goal was to possess Jean's body so she'd be physically substantial again?