When a mouse family gathers to decorate their Christmas tree, the grandmother tells them a story about her favorite Christmas ornament. She holds up a tiny red box with faded writing and tells the story of Posey, a little mouse with an intense curiosity about the contents of the presents under the tree. When she secretly opens all her presents from her parents prior to Christmas and then rewraps them, Posey feels miserably guilty. She worries that she will not get any presents from Santa on Christmas morning, but she does receive her longed-for doll and a stocking full of surprises too, including a tiny red box inscribed with the words “do not open till Christmas.” In the satisfying conclusion, Grandma Posey and her grandchildren hang the never-opened heirloom box on their tree together. Kennedy’s adorable mouse characters complement Dixon’s gracefully written story, which subtly makes the point that peeking at presents doesn’t pay off. (Picture book. 4-7)