Henry and Mudge

Can a boy and his dog be best friends forever? Can that boy have two best friends? Such are the weighty conundrums posed in this simple-hearted family musical based on Cynthia Rylant's book series.

The toddlers in the audience, comprised otherwise of indulgent parents or guardians, find these themes stimulating enough, thank you, as they sit in mostly rapt attention for the show's hour length, clearly delighting in this very cute and very polished production, with its eye-pleasing storybook set by Paul C. Weimer and complementary costumes by Rob Bevenger.

The personable Joan Hess and Patrick Boll play the idealized mom and dad who move with young son Henry to a ramshackle country house, where the boy is desperately lonely until Dad brings home a 185-pound mutt. The pooch helps Henry stop mooning over the absence of his best friend, Cousin Annie.

Joseph Morales as Henry and Todd Buonopane in a plush doggie suit as Mudge — likable players — quickly become the focal point of the tykes in the crowd. And when she comes to visit late in the show, Jennifer Cody's Annie proves a deliciously obnoxious child monster. (You'll be forgiven for cheering when this little showoff's prized dress gets soiled after she's dragged into the woods to help find Henry, who's run away after Mudge switches allegiance to Annie.)

The 10 songs in lyricist-book writer Kait Kerrigan and composer Brian Lowdermilk's score — under Rick Hip-Flores' baton — expound on such basic concepts as "Good Dog," "Roll Over," and (what else?) "Best Friends," the last sprightly choreographed by Devanand Janki. The pleasantly uncomplicated melodies match the kid-friendly directness of the words, with the jivey "Annie's on Her Way" a catchy standout.

Peter Flynn directed with the practiced hand of someone who knows a thing or two about his target audience.

Presented by TheatreworksUSA by special arrangement with the Lucille Lortel Theatre Foundation at the Lucille Lortel Theatre, 121 Christopher St., NYC. Dec. 17-Jan. 20. Wed. 10:30 a.m. and 2 p.m.; Thu., 10:30 a.m.; Fri. and Sat., 2 and 7 p.m.; Sun., 1 and 4 p.m. (Additional performances Tue., Dec. 26, 10:30 a.m. and 2 p.m. No performances Sun., Dec. 24 and 31.) (212) 279-4200 or www.ticketcentral.com. Casting by Robin D. Carus.