Thomas is waiting at the station by the main line for James' train. James is late and when he finally does pull into the station, he is chuffing very slowly. He explains to Thomas that he has to go slowly as he has a very special passenger in a van at the end of the train. The van is coupled to Clarabel. James tells Thomas that the special passenger is a horse that had been injured and needs to go to the farm near the end of the branch line to get better.
At the farm, Thomas watches the horse walk slowly across the platform. When it is time for Thomas' next train, the tank engine can see the horse in a field. When he puffs by, the horse tries to walk across the field, but cannot keep up with Thomas. Each time Thomas passes the field, the horse tries to run alongside Thomas. Over time, the horse gets faster and faster until he could nearly go as fast as Thomas. One day, as Thomas passes the field, the horse runs alongside Thomas as usual. But when he gets to the edge of the field - the horse jumps over the hedge and keeps on running. The next day, a box van is coupled up to Thomas' train; the horse is going home. At the station by the main line, James gets ready to take the horse on the remainder of its journey. Thomas whistles goodbye and the horse gives a big "neigh" as James puffs away.