In London, a diplomat accidentally becomes involved in the death of a British agent who's after a spy ring that covets British military secrets.
The poor, elderly—and the wily, when it comes to parting those who can afford it from their money—Scottish skipper of a broken-down old 'puffer' boat tricks an American tycoon into paying him to transport his personal cargo. When the tycoon learns of the trick, he attempts to track down the boat and remove his possessions.
A successful artist recalls his life in the tenements of the Glasgow slums. In flashback his recalls the events and characters he shared with in a slum tenement building.
