In this game, you play Prisoner's dilemma once against a new opponent each time. Try to maximize the number of points you receive.
You have to take a decision to cooperate or defect simultaneously with the other player. If you both cooperate, each player gets two points. If both defect, you get one point each. If you defect while your opponent cooperates, you will get three points and he will get zero. If you cooperate while your opponent defects, he will get three points, and you will get zero.