In this verbose picture book Hearne (Seven Brave Women, 1997 etc.) hits home the parental dictum, “don’t open the door to strangers.” In an inner-city apartment building, Lizzy and her two dogs are left alone for a few moments by her babysitter. Lizzy remembers not to open the door when someone claiming to be the new janitor knocks and wants to come in to fix the sink. In another apartment, Rowan, Ryan, and their pet rat are also briefly left alone by their babysitter, and they too decline to open the door to the disembodied voice of the janitor. With everyone communicating through peepholes and seeing only the visitor’s lips there is some confusion as to who and where the janitor actually is. In the end the three children, two babysitters, and three pets meet up and become friends as the true identity of the janitor is revealed: the janitor is a woman. Hale’s (Elizabeth’s Doll, not reviewed) illustrations go a long way to improving the story with bold-lined watercolors fairly bouncing with energy and spirited characters. Also contributing to the kid-appeal is sidebar art of the interior of the building that affords an X-ray view of who is going up or down the stairs and elevators. It’s the rhyming and word play, “Wag and Wave and Willy-Nilly and Dizzy-Lizzy” that might keep the reader turning pages, because this mystery isn’t very mysterious. (Picture book. 5-9)