Ghost in the House, A (Apple Chillers) by Betty Ren Wright - Vintage Paperback

Sarah has only one person to turn to.

When Sarah's family moves into her Great Aunt Margaret's house, Sarah can't help feeling something is terribly wrong. She tries to believe she's just unhappy about having to spend so much time caring for her disagreeable invalid aunt. Yet she knows there is more. There's a chill in the air, which only Sarah seems to feel. There are unexplainable heavy footsteps in the upstairs hall. Lights go out, doors slam unexpectedly, and things move by themselves.

Sarah realizes that one other person in the house is just as scared. Aunt Margaret. Together, a sick old woman and a frightened young girl, they must figure out what evil spirit is trying to terrify them.