Lydia Jansen is a faithful and loving wife, though unknown to her husband, a customs inspector, she has become addicted to smoking opium. In the parlance of the underworld this devil's brew is called "hop." Her own father, a politician in the city in which they live, is the head of an opium importing gang, which is the principal medium whereby the addicts obtained their supply of opium. Lydia's craving for the drug is so great, and her desire to conceal the habit from her husband so strong, that she is embroiled in a series of blackmailing attempts by her maid, who is affianced to the stevedore through whom most of the opium is landed from the vessels by which it is smuggled. Her attempts to satisfy her craving for hop, at a time when the government is closing in upon the smugglers, excites her husband's suspicion, and of course he thinks another man has entered her life, and it is only through an almost superhuman exercise of willpower that she finds the strength to conquer her appetite and confess to her husband the terrible habit which she had formed, and thus relieving the terrible suspicion which had grown like a hunting nightmare into his very life. The shock of finding that he himself had contributed to his own daughter's downfall causes the father's suicide and the capture of the entire opium smuggling gang.