When young Ace stows away in Daddy Rat’s bass case, he discovers just how busy a New York jazz musician’s day—and night—can be. Gigging uptown and down, on a cruise boat, a rooftop, in a couple clubs and even, just for the joy of it, on a SoHo street, Daddy Rat discovers that his son in tow has scat-singing talents of his own. Crow’s rhyming text pulses with liberally laced scat—“huggy wuggy boo bat”—and syncopated sound words: “Zow!” Lester’s impressive cartooning chops suit well here: Enhanced pencil-and-watercolor pictures, with a Beats-meet-Hanna-Barbera vibe, convey the verve of city streets and clubs a-bustle with cats and dogs. Daddy Rat, from his Diz-patch and glorious crimson double-breasted jacket down to his toothpick legs in hip slip-ons, is a hoot. Daddy and Ace hail a cab for home and well-earned rest, but kids might well request repeat scat-alouds. Terrific fun. (Picture book. 3-6)