A diminutive, possumlike creature outsmarts monsters, if inadvertently.It snows and the river freezes over. Little Mo's parents, going out to forage, caution him to remain in their cave and not to tread on the ice. But a bored and lonely Little Mo ventures outside anyway and builds snow friends. He hides when enormous, dinosaurlike monsters emerge and settle into the cave. Mustering some courage, Little Mo explains that they must leave. The biggest monster chases Little Mo, threatening to devour him-but, running across the frozen river, the heavy creature falls in. While the other monsters attempt to rescue their pal, Little Mo easily skims across the ice and ascends a snowy hill. He slips and rolls…and rolls, eventually turning into a gigantic snowball. This behemoth panics the monsters, who flee. The snowball splits and opens just as Little Mo's parents return, bearing food. He assures them that he didn't get bored while they were gone, and the gigantic footprints Dad sees belong to visitors he chased off. This cute, if unoriginal, U.K. import will appeal to all readers who fantasize that, though they're small, they can handily vanquish larger foes; kids will root for Little Mo all the way. The illustrations are lively, and the monsters aren't too scary.Let's hear it for all the little guys: Who doesn't dream about getting the upper hand once in a while? (note on prehistoric animals and their evolution) (Picture book. 4-7)