Out the back door

Amelia Tina lightwood moved into a different house with her mother (she never did know her dad) when she was 10. She was always told don't go out the back door. When she asked why, her mother ignored her and turned away. Now she is 18, her mother is dead, and she lives by herself with her aunt who is moving back in with her grandmother. She wants to know now why she couldn't go out the back door. Now she wants to get answers to her questions. What's out the backdoor?