“Once upon a time, there was a big old house.” And in this house live two mice, “little Billy and his big brother, Bo.” Billy and Bo set out to scrounge some supplies—lift-the-flap doors reveal bare cupboards in the mouse household—and room by room, wee Billy keeps trying to warn Bo of danger: “But...look!” Successive flaps lift to show no danger, just a jumble of cleaning supplies or an old tree outside the window. What Billy and readers see, however, is a snub-nosed Persian cat stalking the two mice through the spooky mansion. The large trim of this sophisticated novelty book keeps the focus on the mice and magnifies the cat to terrifying size. Brown’s use of light is masterful; cobwebs festoon the murky corners of each spread, making Bo’s obliviousness credible. The tension ratchets up to a dramatic reveal, which, for a moment, casts the mouse brothers’ survival into doubt. In design and plot something of an anti–Peter Rabbit, this unusual adventure beckons preschoolers ready for a chill or two. (Novelty/picture book. 4-8)