Santa is under the weather, so delivery duties fall to Mrs. Claus.The cheery Mrs. Claus is all business in her bright green skirt and sweater, with green eyeglasses and red striped stockings and cap. When she and some industrious elves can't roust Santa from bed, she offers to save Christmas Day. Rhyming text matches the mood of this fast-paced story, from Santa's "I'm stuffy. I'm sneezy. I'm slow as a yeti. / My big ho-ho-ho isn't holiday ready" to "She had to act fast to untangle the rein. / ‘I may not have magic, but I've got a brain!' " The text is part of the design—shouted words are in very large type that often curves through the sky. The illustrations are bright and expressive. The close-up of Santa's bleary face as he inhales steam from his cocoa is a wonderful complement to the smiles on the elves' faces as they take orders from the new boss. She maps out her route and solves whatever mishaps she and the reindeer encounter, from tornadoes and blizzards to a hole in the sleigh that leaks multicolor splashes of color. All of the denizens of the North Pole present white.Young children will enjoy this exuberant adventure. (Picture book. 3-6)