Robert Walton is searching for the North Pole. He is a very ambitious sea captain who wants to be the first to sail there, no matter what the risks are to him or to his crew. He rescues Victor Frankenstein while on this dangerous voyage, and from him learns the cautionary tale Victor knows all too well: beware of blinding ambitions (Victor, of course, has learned this lesson too late through his creation of a "monster" in his desire to play God). Captain Walton luckily takes the lesson to heart, abandoning his quest for the sake of safety.
Robert Walton is sending letters to his sister and he is looking for the North Pole but at the same time he is looking for a companion. He rescues Victor Frankenstein and from there the whole story becomes released of how Victor had created the monster and what havoc it created. Victor tells a cautionary tale and that he has learned his lesson far too late but tells Walton how he should be careful.