"A Voyage with Captain Dynamite" is the story of three boys going out from Cottage City in a small yacht who are caught in a storm and run down by a larger vessel, a fillibuster. They are rescued by Capt. Dynamite, who carries them off to Cuba. There, having sent word home that they are safe, they take part in many adventures and do, perhaps, a little more than a boy outside of a book would be able to do. Harry Hamilton rescues Juanita, a young Cuban girl, who is in prison, and who escapes in his clothes.