This video introduces the concept of game theory, explaining how it applies to decision-making in various situations, from personal interactions to international relations. It uses the "prisoner's dilemma" as a foundational example and discusses the results of Robert Axelrod's iterated prisoner's dilemma tournament, highlighting "tit-for-tat" as a surprisingly effective strategy. The video argues that this strategy, characterized by niceness, retaliation, forgiveness, and clarity, can lead to more successful and cooperative outcomes in life.