Slate Shannon, an American expatriate living in Trinidad, runs a hotel and travels in a boat called Bold Venture. He cares a ward named Sailor, the daughter of a late friend. Shannon is a detective and deals with baffling cases. Slate Shannon is commissioned to transfer unidentified cargo from a Caribbean steamer to Jamaica in his sloop "Bold Venture". He and Sailor witness a murder before they learn the nature of the mysterious cargo- contraband guns. The gunrunners plan on forcing Shannon and Sailor to land the guns and then kill the couple.
