In a picture-book mystery for young readers, Yolen pays homage to the world of Upstairs, Downstairs, to Beatrix Potter's animal/human characters, and to not only Agatha Christie but Conan Doyle. The servants' preparations are complete; the Reynards are ready to receive. Piggins the butler announces Inspector Bayswater (a hound), his friend Professor T. Ortoise, Lord and Lady Ratsby, and elderly explorer Pierre Lapin with his three unmarried sisters. In the midst of dinner, the lights go off; in the confusion, Mrs. Reynard's diamond necklace disappears. Bayswater is stumped, but the alert Piggins assembles several clues and pinpoints the Ratsbys as culprits; the Misses Lapin foil a getaway attempt; then Piggins oversees the washing up and concludes the evening with a pot of tea. Yolen's staccato style gives this the air of a satirical synopsis; the events are barely mysterious, but they're humorous and fun. Dyer's carefully detailed interiors have the charm of a period dollhouse; her animal characters have a comic individuality. There aren't many mysteries available on this level; this one should serve nicely.