The coffee-drinking, torte-nibbling Officer Hippo has his mind on one thing: how to get through the requisite Officers' Ball despite not knowing how to dance. As Yee (Mrs. Brown Went to Town, 1996, etc.) tells it, Officer Hippo sneaks away from crime- solving to take dancing lessons with Madame Lafeet; after hoofing his way through a typical day of standard police business, he arrives at the ball, still secretly practicing. ``ONE-two-three- ONE-two-three/Needles and pins,/ONE-two-three-ONE-two-three . . ./The ball begins!'' Not surprisingly, he musters up the courage to ask Officer Mole (his attention-grabbing partner) to dance; they hokey pokey, disco, and jitterbug their way to become king and queen of the ball. The rhyming text is manipulated into a storyline that sounds forced and flat. Comical animal characters appear against humorous background details: ``Wanted'' posters feature criminal mice and bunnies, snakes take a backseat in cabs, and pizzas fly. Still, this is not just another hippo-to- the-rescue story with a Broadway-style finale. Readers won't be surprised by the ending, but it certainly has panache. (Picture book. 3-5)