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.