Ralph Redwood’s uncle dies leaving him sole heir to all his possessions, including a very large and beautiful diamond ring, under the stone of which is hidden a diagram showing the location of his wealth. Upon news of the uncle’s death, Ralph telegraphs his lawyers that he will leave on the next boat. Jasper Rowels, a bad character, hears of Redwood’s fortune and that night secrets himself on the boat. At a favorable moment, he hurls Ralph overboard, and taking the ring, assumes Ralph’s name and stateroom. Ralph is rescued, but Jasper denounces him as the badly wanted crook, Jasper Rowels, and Redwood, having no means of identification, is placed in prison when the boat arrives. Meanwhile, Jasper visits with a young lady on board, and becoming quite smitten with her, gives her the diamond ring, quite unconscious of its peculiar secret. Incidentally, the young pair have their picture taken with the young woman wearing the ring. When he calls on the lawyers, Jasper is amazed to be asked for the ring. He promises to produce it, calls on the young woman and learns that her handbag containing the ring had been stolen by thieves that day. In this predicament Jasper thinks of the photograph and has a local jeweler make an exact duplicate. The lawyers accept this proof of identification, and leading him to the uncle’s villa, tell him that beneath the stone of the ring he will find the secret key to the hidden wealth. Meantime, Redwood, with the aid of Rosa and her brother, two good persons with whom Redwood had become acquainted, succeeds, by swimming through a long stretch of water in escaping from the prison. He arrives in the city incognito. Jasper finding hope nearly gone, advertises a large reward for the return of the stolen ring. One of the thieves carries the ring to his villa. The young woman, passing by in an automobile on the way to Jasper’s home, is seen by Redwood, who leaps on behind. Arriving at the gate, he notes the thief who has the ring, vaingloriously flaunting it in the face of a maid. A fight follows in which Redwoods gets possession of his ring. The thief follows him to the home of Rosa and takes down the address. Finding Rosa alone some time later, the gang members, along with Jasper, seize and kidnap her. She is found to hold in her clenched hand the important diagram, although the diamond itself is still in the possession of Redwood. With the diagram, Jasper hurries to the villa. He pries open the great vault, steps inside and in an instant he is made prisoner by the slamming of the heavy door. Rosa’s brother, receiving the threatening note in which her life is claimed as a forfeit unless the ring is produced, succeeds in rescuing her. Ralph Redwood, meanwhile, goes to the villa, and, with the ring, easily opens the vault door, only to stumble over the body of Jasper. Thus Redwood comes into his rights. He goes home to ask Rosa to share the fortune with him.