The epicenter of the plot of the third part of once again being Marty McFly, which never ceases to travel back in time. Thanks to the development of the dock in science move forward and back in time to become real. This time the guy gets a mysterious letter from his friend Emmett Brown, who is in the nineteenth century. He writes that he is all right and asks you not to worry about his fate. However, in the newspaper, he finds a story that says that the scientist killed in just a few days after sending the message. In the future, when Marty has promised never to interfere in the course of history, a lot of things have changed, because the young man decides to go back in time to meet the Wild West. Here he is witnessing conflict Brown and gang leader "reservoir dogs" of a certain Mr Tannen's. A few days later, the scientist will kill this man. And earlier, Martin was forced to flee from the Indians, cavalry and a rabid bear.