(Collab with Latecomer who suggested the idea. Takes place after "The Hearth's Warming Club".)

Even though he and his friends are staying over the holiday break to be with Gallus, Sandbar has made his own plans for Hearth's Warming. Those plans get upended when his parents have to leave and unexpectedly task him with foalsitting his baby sister, Coral.

Despite Sandbar having some prior foalsitting experience, he decides to rope his friends into helping him with his important assignment. Which is quickly complicated by the fact that none of them know how ponies raise their young.

To complicate things further, Sandbar is soon hospitalized after hitting his head against a tree. So his friends have to take turns checking up on him, and keeping Coral under control. A problem when she is going through "potty training" which is something Sandbar's friends know very little about.