John Strong and his adopted son, Hal, are inveterate chess players. Hal, en route to a summer resort, meets Vivian Carew, an unscrupulous woman. Discovering that Hal is the adopted son of John Strong, a man of wealth, the woman resolves to fascinate the boy. John Strong arrives on the scene. The woman has progressed with her wiles. William Clark, a friend of Strong’s, tells him that Miss Carew has had an unsavory past. Strong does all he can to persuade his adopted son to cast aside the woman, but the boy is too infatuated with the woman to listen. Then Strong takes a hand in life’s chess game. He visits Vivian Carew and when she refuses to listen to his pleas to throw over the boy, he tells her of his knowledge of her past. It is checkmate for the woman, who immediately takes passage for Japan. Then it is that Strong and the boy resume their chess games.