Ralph Manson, who marries Leonore Fenwick, is led astray by a stage siren. His wife obtains a divorce, and is aided in sending her son to college by Robert Hadley, who induces her to live with him under promise of marriage as soon as he can obtain a divorce. His wife dies and he refuses to keep his promise to Mrs. Manson. The son, finding a check given by Hadley to his mother, has his suspicions aroused. The son demands an explanation, but his mother declares it was only a business matter. Then follows a scene between the son and his mother's lover, in which Hadley, after being enraged by the boy's words, disregards the plea of Mrs. Manson and tells the son the whole story. This causes the mother to lose her reason and she shoots Hadley. Mrs. Manson is tried for murder. The jury acquits her on the ground of temporary insanity, holding Hadley responsible for her loss of reason.