The Ghost at Dawn's House (the Baby-Sitters Club #9)

Dawn has always thought
there was a secret passage hidden in her house. But she never thought
there was a ghost... until now. All kinds of creepy things go on
whenever Dawn's at home. There are even spooky noises behind her bedroom
wall!Dawn is sure there's a ghost in her house. And so
are the other Baby-sitters. But they're so busy with their baby-sitting
jobs that they hardly have time for a ghost hunt. Will Dawn and her
friends ever solve the mystery, or will Dawn have to share her house...
with a ghost?