It is spring in the Isles of Scilly. Gussie Smith is in trouble. Actually he is usually in trouble, but this time things are worse than usual. Welfare Snell, the slimy Truant Officer, is trying to get Gussie deported to the mainland (which he loathes), and Grannie Dole - his guardian - locked up in the Bide-a-wee Home (which she despises). Moreover, he is deeply involved in the affair of the tin leg of Arthur Hopcraft (of the Civil Service Birdwatchers' Association). In addition, the weather is changing, with full gales expected, and Gussie naturally finds himself at sea in an open boat.