Letter 3: In this short letter, Walton simply tells his sister that he and his men have started the voyage and everything is going according to plan thus far.
Letter 4: This letter is the only one of any real significance. Walton and his men have by this time gone so far north that they have begun to encounter ice caps. One day, during a windstorm, Walton says that they spied a huge figure in the distance traveling on a dogsled. Later, to their amazement, they encountered another man stranded on a sledge that had floated towards the ship on a piece of ice. Eventually this man comes aboard, only after finding out the ship is going north. This, of course, confuses Captain Walton, who gets to know the man over the space of a few days. Walton concludes his letter, saying that the man has agreed to tell him his story. This is where the real narrative (from the perspective of the man-Frankenstein) begins.