Mary and Billy are sweethearts. Mr. Stanley, the girl's father, suspects the boy of being a victim of the drug habit. Billy, in an attempt to master his craving, abstains from the drug. He is invited to dinner at his sweetheart's home. Stanley notices the boy's nervousness. He resolves to call upon him at his office and learn the truth. The next day, Billy's desire for the drug becomes so intense that the moment his employees leave the office, he brings out his hypodermic. Stanley and Mary arrive in time to see Billy about to take the drug. They discover his terrible habit. Mary's love for Billy is so great that she resolves to help him win his fight. The boy is taken home. Mary and her father promise to call to see him that night. Several hours later, Billy's desire for the drug is so great that he struggles desperately with his servant in an effort to get at the box lying on his dresser. Stanley and his daughter arrive and help subdue the boy. Mary pleads with Billy and once again implants within him the resolve to conquer the habit. The following day, Mary sends her sweetheart a rose. When his craving causes him untold agony. Billy clutches the flower. It typifies the girl he loves and exerts a soothing influence over him. Several months pass by. Each day Mary sends the boy a fresh rose. His craving grows weaker and at last Billy knows he has conquered his invisible foe. With joy in his heart, Billy breaks the news to Mary and wins her for his wife.