Sarah's blind cousin, Mary, comes to Horseland for a visit. Sarah is busy training a new horse so she lets Mary take care of and ride Scarlet while she is visiting. Bailey, Molly, and Alma are concerned with leaving her by herself, so they constantly follow her around offering to do everything for her. However, when the four of them get lost on a new trail at night, they soon begin to understand that Mary is not as helpless as they think she is.