The boys are indoctrinated into a mysterious chain of secrets, lies, and treachery after accidentally reading a cryptic letter from someone (or something) named "Robin." The more they investigate this "Book of Secrets" (which contains confessions of lurid crimes by Jessi, Mallory, Stacey, Kristy, Claudia, Dawn, and Mary Anne), the more they are rebuffed, first by agents of Scholastic, then by someone who is far, far closer to them. As the net of the Baby-Sitters Club Chain Letter closes around them, they understand—too late—the meaning of the four words that started it all: Secrets. Will. Always. Kill.Thanks as always to original Baby Boy Scott Lamb for the intro music, and to Bye Bye Empire for the outro music.