Mary Anne should never have thrown away that chain letter she got in the mail. Ever since she did, bad things have been happening — to everyone in the Baby-sitters Club. With Halloween coming up, Mary Anne's even more worried — what kind of spooky thing will happen next? Then Mary Anne finds a new note in her mailbox: Wear this bad-luck charm, it says. OR ELSE. Mary Anne has to do what the note says. But who sent the charm? And why send it to Mary Anne? If the BSC doesn't solve this mystery soon, their bad luck might never stop!