A new rule is put in place where the engines can only have one washdown per day, which leaves Percy cross, as he has all the dirty jobs. He desperately tries to not get dirty and finds a train of sugar for the chocolate factory. He thinks he will stay clean doing this job, but he could not be more wrong.

During a snowstorm, Toby is flagged down by Farmer McColl, whose sheep are due to give birth and urgently need a vet. At the next station, Toby explains and Duck and the vet set off for Farmer McColl's Field. However, even Duck's snowplough cannot cut through the snow and they are forced to retreat. Now, Toby must use his old line to save the lambs.