Captain Dixon, receiving a message from the custom office that there is a band of smugglers operating on the islands off the coast, bids his wife good-bye and goes on the assignment. At the island wharf he inquires of an old sailor for the most quiet lodgings in the place and is led to a hut where lives an elderly man, supposedly s fisherman, and his pretty daughter, Bess. The old man does not at first want to admit the stranger, but the sight of handsome board money quickly changes his mind. Bess leads him to his room. That night Dixon is still unpacking when a noise downstairs arouses his suspicions. He goes down and discovers the old man leaving the house stealthily with several rough-looking strangers. He follows them and learns that they are the smugglers for whom be was sent in quest, and Bess' father the leader of them. Hurrying back to the house, the captain discovers Bess waving a red lantern in the window (the secret danger signal), for she had heard him depart and suspected his mission. She had also learned through a photograph in his room that he was married. Dixon attempts to remove the light, but is forced by Bess at the point of a revolver to wave it. The smuggler and Bess' lover, heed the signal, and, returning, put Dixon out of the house. The latter, however has formed a wild desire for Bess and, meeting her on the beach, attempts to force his love on her. Failing in this he sends her a note to the purport that if she does not meet him on the pier at once he will expose her father. Bess' love for her aged father is stronger than anything else, so she sadly decides to sacrifice herself to save his life. She had not left the house long, however, when her father and Ned find Dixon's vile note. They hurry to the pier in time to frustrate the captain's designs, but in the melee, the officer falls into the sea.
—Moving Picture World synopsis