Fresh from an encounter with ghost mastodons (Six Haunted Hairdos, 1997), Miss Earth's fifth-grade class readily takes on a new challenge in this eccentric holiday story from Maguire. When Mayor Timothy Grass disappears, all of Hamlet, Vermont, is abuzz with minors; in Miss Earth's class, opinion is about evenly divided between the Tattletales (girls), who think he fell into a time warp, and the Copycats (boys), who blame Bigfoot. Neutral Pearl Hotchkiss's suggestion that he was abducted by aliens is discounted, but she's right. Having glimpsed a Christmas movie on the visor screen before their crash landing, five aliens from planet Fixipuddle are out to free the slaves from ""Santa Claw's"" workshop and end his evil domination of the world; when Mayor Grass strolls by, still in his Santa suit from a school visit, they tie him up and apply tickle torture to make him reveal the location of his Fortress of Fear (the workshop). After an unsuccessful attempt to disguise themselves as Keebler-style elves, the aliens recruit Lois Kennedy's beagle, Reebok, to spy for them, equipping him with a universal translator that allows him to talk. Their mistake: Reebok's a double agent. The Tattletales and Copycats accept Reebok's story, put aside all rivalries, and spring into action, converting the classroom into a ""workshop"" of broken toys for the aliens to ""liberate."" This clever comedy, with humor both broad and sly, has the odd combination of hilariously fractious aliens and a generous measure of Christmas cheer--but it works.