Oliver is glum only shunting in the yard, and takes it on the trucks, causing an accident. He is put on mail duty instead. A signalman dozes off and they end up going down an old branch line.

The Fat Controller and his family go on holiday, though things start to go wrong. A low-flying bi-plane named Tiger Moth goes missing, so the Fat Controller and Harold search for it. He decides to go boating on a canal instead, though they become bogged down in mud.