When the somewhat disreputable Martin Beckwith builds a midget submarine that uses a novel form of propulsion, he has little idea that an unlikely gang of buccaneers plans to commandeer his vessel for their own nefarious purposes. The daring heist is masterminded by a crafty naval officer called the 'Admiral' from his garden in a leafy Hampshire village and draws together a disparate band of crewmates which includes a feisty female naval officer, a young executive, an attractive pub landlady. In this light-hearted tale, the Admiral and his unlikely buccaneers are pitched against the inventor, who will stop at nothing to get his submarine back in some South Coast Shenanigans.