The Maggie is a typical Clyde puffer, a small, aged cargo boat with a varied, irascible and argumentative crew. MacTaggart (Alex Mackenzie), her rascal of a captain, is in dire need of £300 to renew his licence. In a shipping office by chance, he meets Mr Pusey (Hubert Gregg). Pusey, a proper Englishman complete with bowler hat and umbrella, is trying to arrange for the transportation of some personal furniture for his boss, American Calvin B. Marshall (Paul Douglas), as a present for his wife to furnish their new home. The big company has no ships immediately available, but MacTaggart gets the job when Pusey mistakenly believes that he works for the reputable shipping company and that the more modern vessel docked next to the Maggie is MacTaggart's.
Marshall is a wealthy industrialist, a stubborn and determined self-made man. When he eventually learns the truth, he sets out in pursuit of the boat by aeroplane and hired car. Catching up with the puffer, he puts Pusey on board to ensure the cargo is transferred to another boat. But his underling is no match for the captain; he ends up in jail on a charge of poaching. Marshall realizes that he will have to handle the matter personally. After another costly chase, he boards the boat himself to spur the transfer of his cargo onto another vessel. However, the route and timing of the voyage are governed by tidal variations and local community priorities.
Marshall's hostile attitude gradually softens somewhat. He is particularly touched by the loyalty of the "wee boy", Dougie (Tommy Kearins), to his captain. At one point, when Marshall threatens to buy the boat from the owner, MacTaggart's sister, and sell it for scrap, Dougie drops a board on him, knocking him unconscious. His mood changes again when the wily Mactaggart moors the puffer under a wooden jetty across which the furniture must be carried in order to offload it; as the tide rises the jetty is torn apart, making unloading impossible.
At one of the stops, the crew attend the hundredth birthday of an islander and Marshall chats with a nineteen-year-old girl who is pondering her future. She has two suitors, an up-and-coming, ambitious store owner and a poor fisherman. The American advises her to choose the former, but she believes she will marry the latter, explaining that he will give her his time, rather than just things. This strikes a chord with Marshall. He is having marital difficulties and the furniture is an attempt to patch things up with his wife.
As they finally near their destination, the engine fails; caught by wind and tide on a lee shore, it falls to Marshall to find and fix the problem, practically beating the elderly engine into submission to get it to run. But the Maggie has drifted too close inshore and the repaired engine drives the boat onto the rocks. Marshall knows that if they jettison the cargo, the lightened puffer can be floated off safely. Mactaggart, however, informs him that he has failed to insure the furniture. Marshall orders the furniture be thrown overboard anyway.
At journey's end, Marshall even allows Mactaggart to keep the money he so desperately needs. In appreciation of his magnanimity, Mactaggart renames his boat the Calvin B. Marshall.Alex Mackenzie as Captain MacTaggart
Paul Douglas as Calvin B. Marshall
Tommy Kearins as Dougie, the wee boy
James Copeland as the Mate
Abe Barker as the Engineer
Hubert Gregg as Pusey
Dorothy Alison as Miss Peters, Marshall's secretary
Meg Buchanan as Sarah MacTaggart, the owner of the ship
Geoffrey Keen as Campbell, the owner of the large shipping company
Mark Dignam as the Laird who jails Pusey
Roddy McMillan as the Inverkerran driver
The Maggie was played by two Hays boats in the film, the Boer and the Inca. Much of the film was shot on location at Islay. The film uses real placenames as far as the Crinan Canal, then switches to fictional placenames once they get through it. the film's working title was "Highland Fling", during filming in the summer of 1953, but was changed to The Maggie before its release in early 1954.
The Maggie has to date only seen official release in the UK. Initially issued on VHS in 2002, a DVD followed in 2006 and was included alongside three other films in The Definitive Ealing Studios Collection: Volume Four. A digitally restored version was issued on Blu-ray and DVD in 2015, containing for the first time, subtitles and extra features.