Dr. John Carey, a noted blood specialist, convinces philanthropist Jules Le Moyne to finance Berlin chemist Emil Hartsell's search for a cure for syphilis. Hartsell's research proves successful, but following Le Moyne's death, the chemist breaks his pledge to give the formula to society and contracts with New York profiteer Adolph Keller to sell the drug at a price prohibitive to the poor. Representing his father in New York, Karl Hartsell becomes engaged to Keller's daughter, Alice. Meanwhile, Lennon Morrett, an artist's model, contracts syphilis from roué M. Saccard, but can't afford the drug. When Dr. Carey is about to intercede and obtain the drug for her, Keller instead sells it to Saccard. Believing that society is responsible for her fate, Lennon sleeps with a lot of men. She blames Karl because his father has made the drug too expensive, and during his bachelor's fling before the wedding, she gives him the disease. Dr. Carey meets the elder Hartsell in Holland and pleads for the drug to be distributed cheaply in America, but Hartsell says America means nothing to him. Although Dr. Carey finally persuades the greedy scientist of his son's illness, Hartsell refuses to give Carey the formula and arranges to treat Karl himself in New York. Because the United States and Germany are at war, Hartsell's submarine is torpedoed off the New York coast, whereupon Karl walks into the waves to join his drowned father. Later, U.S. scientists discover a cure superior to the German formula.