Thomas and Percy's Mountain Adventure' - US/'Thomas and Percy's Christmas Adventure - UK is the twenty-sixth episode ever made in Season 3.
Thomas is looking forward to delivering mail to the people of the mountain village, but when Sodor is struck by a snowstorm, the mountain village is snowed under. Thomas is summoned to help and Percy takes the mail for him. On the way there, however, a fogman stops him and sends him to get help. Percy tells Harold as Thomas arrives with Terence and asks Percy to tag along to help with the rescue. Harold drops hot drinks and food for the villagers and Terence clears the streets. As a token of gratitude for their hard work, the villagers make a surprise. When the engines wake up, they see the shed decorated with new paint and Christmas decorations and agree it is the best Christmas ever.
- Some of the parcels Harold drops hit the people.