It's time for the First Annual Blue Moon Stables Christmas Party! Mrs. Fitzpatrick, the owner of Blue Moon Stables, is celebrating the holidays with a party for her young riders, and her students have been looking forward to the event for weeks. Once the party starts, however, the weather takes a turn for the worst. Snow and ice threaten to derail the festivities.To Mrs. Fitzpatrick's horror, Sadie, one of the horses boarded at Blue Moon, becomes ill during the storm, and the prizes for the party games, including the prize horseshoe, go missing!Will the Christmas party be ruined? Can Sidney and her best friend, Jane Abbot, help Mrs. Fitzpatrick find the missing horseshoe and the other prizes? And what will happen to Sadie?.