All at Sea is the 70th episode of Thomas and Friends
One day, Duck and Percy notice the horizon is packed with sails flapping against the blue skies. Duck then tells Percy that he wishes he could sail to far away lands, but Percy thinks it is silly since engines cannot float. Harold soon arrives and tells the two engines that the boats are there for the Regatta and that it is his job to hover around in case he is needed. Duck then asks Harold if he has ever been to the horizon and Harold says he has been beyond the horizon and can also land on ships (aircraft carriers), anywhere, anytime.
Duck then goes on talking about the regatta all day, making Percy lose patience and he tells Duck that their rails can take them to all the places they could ever wish to see. Suddenly, the harbour emergency siren goes off, as a man taking part in the Regatta has suffered a hand injury and Duck is to take him to hospital at the next station. Harold brings the man ashore and Duck quickly races over. Harold tells Duck that it is his job to stay at sea in case of other emergencies, otherwise he would take the man to hospital himself. Duck soon makes his way down the line. When Duck and the man arrive at the station, the man thanks everyone and Bertie gets ready to take him to hospital. Bertie then compliments Duck saying that he looks splendid flying along the line and it is no wonder they call him "Great Western." Duck then agrees with Percy that engines are happiest when their wheels are firmly on the rails.
The same night, Duck and Percy stay longer at the quay, when Duck notices a shooting star. Percy laughs and tells him that it is Harold hovering overhead. Something flutters down towards Duck and his driver manages to catch it. It is a flag from the Regatta and Harold has given it to Duck as a present, which Duck sees as kind of Harold and he begins to understand just what an engine needs.
Nowadays, Duck dreams about travelling to the horizon; but now realises, that sometimes the best travels are those that can just be dreamt about.