Graveyard Kids

For Vivien, the worst part of living in a graveyard has got to be at night when the gates clang together like the dead are trying to escape. Or it could be the funerals and crying people all the time. Or maybe it's how she thinks the other seventh graders at her new school will treat her when they find out her house is surrounded by corpses.
No, life at the cemetery isn't perfect, but it does hold a fascinating mystery. Vivien discovers a gravestone belonging to a woman who was born in 1863, but there's no date of death on it. The woman would be 150 years old, so Vivien knows she can't still be alive. But if she died, why isn't the date carved on her headstone? Did someone just forget, or is it something else? Vivien wants a logical explanation, but she keeps coming back to her goofy little brother's belief that the woman was never buried because she's a vampire.

Vivien needs to solve this mystery fast before she has to admit that vampires are real and her brother is actually right about something.