When he returns from fighting in Vietnam, Vince Majestyk moves to Colorado to become a watermelon farmer. Although his intention is to lead a peaceful life, before long he finds himself in jail. While there, he crosses an organized crime boss named Frank Renda in exchange for his own freedom. So when he is released from prison, Vince finds himself the prime target of the mob. Now in addition to extorting money from all the farmers, they begin to beat up his field hands and machine-gun his crops. So Vince teams up with a Chicano activist named Nancy Chavez and starts to seek retribution against them.