Need help with ending in my short story?

Okay I've been writing a story about a young girl around eight years old. Her family just moved into a haunted house. A family before them had died. After a short while her parents come up missing. Its up to her and her live in nanny to find her parents within 48 hours or the child protective services will come and remove the girl from the house. I have what I'm going to do but its supposed to be a scary story and I don't have any ideas how her parents will return. I'm stuck. any ideas