It is Christmas time on Sodor and Henry is alone at the sheds. He is not happy; he wants to be busy like all of the other engines. Soon, the Fat Controller arrives and gives him a special job. He has to take a special box from the docks to Farmer McColl's field and then tell the other engines to go to the field at teatime. The Fat Controller also tells him to take special care of the box. He has soon collected it and taken it to Farmer McColl's field. When it is unloaded, he is worried about leaving it all on its own in there, but he knows he must tell the other engines to go there, so he chuffs off.
He first meets Gordon at a junction, but is too worried about the box to tell him to go to the field. Instead, he hurries back there to check on his box, only to find that it is gone. In its place are five Christmas trees. He worries that the Fat Controller will be displeased, so goes to find the missing box. While looking for it, he meets Toby and James at a junction, but he is so distracted about his box, he does not tell them to go to the field at teatime. When he arrives back at the field, he sees even more Christmas trees - but no box. At Bluff's Cove Junction, he meets up with Thomas and Percy, but he does not tell them to go to the field at teatime because he is still too distracted by the missing box.
Henry continues looking for his at the Fenlan Track, Maithwaite station, and sidings, but he cannot see his box anywhere. He sadly steams back to the field, where he sees an entire field of Christmas trees. The Fat Controller is there and explains that they were inside the box. Henry feels silly and knows that he must tell the engines to go there at once. He soon tells them all and, later that night, they all gather there. However, the Fat Controller is absent. Suddenly, the trees are lit up by colorful festive lights and out from the forest comes the Fat Controller, dressed as Father Christmas.