A small, blatant misunderstanding that doesn't work even on its own limited terms. Sisters Lucy and Toby (whose ages are indiscernible, and who are sometimes drawn the same size) watch a new family move in next door, see ""a little girl"" arrive (who does look little--younger than both of them), then see the mother plant a sign on the lawn saying ""Watch Out for Horrible Hannah""--and assume, very dubiously, that the sign refers to the little girl. So Toby proceeds to act like a gorilla, Lucy to act like a ghost, all to put fear into the little girl--who does run inside and, after further Toby and Lucy shenanigans, calls out ""I hate you."" The next day a big, gentle-looking collie-ish dog is delivered by the vet, who assures the mother that ""Hannah is not a mean dog. She was very sick. That's why she was jumping on people. . . ."" Down comes the sign; Lucy and Toby write the little girl an explanatory, conciliatory letter; and she promises she'll come over the next day and tell them what they keep asking her--namely, her name-that-isn't-Hannah. But the book ends forthwith, without our learning it. It's implausible, it's insubstantial, and ultimately it's unsatisfying.