Wait Till Helen Comes by Hahn
Heather is such a whiny little brat. Always getting Michael and me into trouble. But since our mother married her father, we're stuck with her...our "poor stepsister" who lost her real mother in a mysterious fire.
But now something terrible has happened. Heather has found a new friend, out in the graveyard behind our home -- a girl named Helen who died with her family in a mysterious fire over a hundred years ago. Now her ghost returns to lure children into the pond...to drown! I don't want to believe in ghosts, but I've followed Heather into the graveyard and watch her talk to Helen. And I'm terrified. Not for myself, but for Heather...