America's favourite baby-sitters are detectives, too!
While cleaning up Granny and Pop-Pop's house after a flood, Mary Anne finds a secret panel in the basement wall. Hidden behind it is a package marked with a threatening curse.
What's inside doesn't look sinister at all: It's a beautiful music box. But Granny swears it's not hers. And suddenly, a lot of odd things are happening at Granny and Pop-Pop's house.
Was the curse real? Who put the box there - and why? If Mary Anne and the BSC don't find some answers fast, they may wind up in serious trouble!