It is foggy in Greendale and Pat is driving carefully along the road. He soon arrives at the post office late, but there is no sign of the letters yet, so Mrs. Goggins invites him into her sitting room for some tea and biscuits. Then before Pat can eat his favourite biscuit, the postman from Pencaster arrives with the mail. Pat helps Mrs. Goggins to sort the letters and is soon on his way again.

On the way, the lights on Pat's van are not much help in the fog, so he stops to check a sign post, only to discover that it is a crossroads sign. Pat does not know which way to go, so he walks along the road, trying to see through the fog without losing sight of his van. Suddenly, he sees someone standing in a field. Pat thinks it is Ted Glen out after rabbits, so he goes over with a letter for him. Pat touches Ted on the shoulder, but he does not move. Pat puts the letter in Ted's pocket. Still, he does not move. Finally, Pat gives him a nudge. The figure spins round and it turns out to be a scarecrow. Pat feels very silly, but luckily no one has seen him, so he says goodbye to the scarecrow and makes his way back to the road. Alf Thompson passes by on his tractor and shows Pat the correct way to go. Pat is on his way again and he soon sees Sam Waldron at the side of the road. Pat stops to buy some cough sweets from him.

The next stop is at the church and Pat gives some letters to the Reverend Timms. The Reverend remarks that not even fog will stop Miss Hubbard coming to choir practice. When Pat returns to his van, he discovers that Jess is gone. Pat goes out into the fog to search for him. He soon finds Jess, but now they are both lost in the fog and cannot find the road again, let alone his van. Meanwhile Miss Hubbard finds Pat's van on her way to the church, but there is nobody inside. She and the Reverend ring the church bells and Pat is able to find his way back. Back at the church, Pat has had a cup of tea prepared for him and there is also some milk for Jess. Suddenly Miss Hubbard spots the sunshine coming in through the stained glass window. A breeze has blown the fog away, so now Pat and Jess can deliver the post without any trouble at all. As they drive along in the van, they spot the scarecrow again. Pat reckons that he is still waiting for a letter.

Heavy snow has fallen in Greendale and Peter Fogg is clearing the roads with his tractor and bulldozer blade. When Pat calls at the Post Office, Mrs Goggins warns him about the ten foot drifts up at Intake Farm and gives him a parcel to take to George Lancaster at Hill Top Farm. Pat calls at Greendale Farm, where Katy and Tom throw a snowball at him. He throws one back, but it hits Alf by mistake. But Alf doesn't mind at all, as he knows it's only a bit of fun. The road is blocked and the tractor's bulldozer blade is stuck in a snowdrift. Pat offers to help Ted and Alf dig it out. After giving Mrs Pottage her letters, he sets off.

Peter is already digging when the men arrive. They help him dig the snow away. Peter tests the tractor. At first, the snowdrift doesn't move. He reverses the tractor and tries again. This time, he gets through. With the road now clear, Pat says goodbye to the twins and sets off again. He calls at the vicarage with a letter for the Reverend. But Dr Gilbertson is also there, as the Reverend has fallen on the ice and broken his leg. Pat gives him the letter and offers to deliver the Parish Magazines for the Reverend. Pat then goes up the hill to Thompson Ground.

When Pat arrives, he is told by Mrs Thompson that Peter had to go back down the hill because the snow was so bad. Pat plans to walk to Hill Top but Alf offers to take him on the farm sledge as he has to take some food for the sheep. Pat and Alf load up the sledge. Mrs Thompson gives them some groceries to take to George. They set off. The sheep are glad to see them. Pat and Alf notice that George's house is nearly buried! Since George is not in, Pat leaves the parcel and the groceries on the table.

Pat and Alf go back to Thompson Ground. At first, they fall off the sledge and tumble down a hill in the snow, but they get back on it and ride it all the way back. It crashes into the farm shed. Pat and Alf go inside for a cup of tea. Pat thanks Alf for the ride and sets off in his van. The rest of his round is in the valley. The roads have been cleared and gritted. Pat jokes to his cat: "No more digging or sledging today. It takes more than snow to stop us, Jess."