On an icy winter day, Wilson and Koko are sent out to sand the tracks in the mountains. Wilson is having too much fun exploring to keep his mind on the job. He doesn't realize that an icicle has fallen into his sand wagon, wetting the sand and rendering it useless. He's stuck! He figures out a way to dry the sand by using the heat from his engine and makes it back to the depot -- after finishing his job, of course!