Abigail Reed and her younger sister, Becky, are always at each other's throats. Their mother calls them the September Sisters, because their birthdays are only a day apart, and pretends that they're best friends. But really, they delight in making each other miserable. Then Becky disappears in the middle of the night, and a torn gold chain with a sapphire heart charm is the only clue to the mystery of her kidnapping. Abby struggles to cope with...