Victor is by now very unwell but is nursed back to health by his closest friend, Henry Clerval. Together the two go travelling to Italy. Just as they are about to return to Victor's home, they receive the news that the youngest Frankenstein, Victor's infant brother William, has been tragically killed. The blame has fallen on Justine Moritz, a trusted servant of the Frankenstein family, but Victor sees his creature near the scene of the crime lit up by lightning flashes. He realises the truth about William's death but also knows that nobody will believe his fantastic story. The innocent Justine is tried and executed, so she and William become the first to fall victim to Victor's ambition.
A guilty Victor goes alone into the Swiss mountains where, eventually, he meets up with the Monster. He is surprised to find that not only has the thing he made survived, but that it also has the power of language. The Monster tells a long story about how he has secretly lived in an outbuilding next to the De Lacey family following their lessons as they teach a foreign visitor their language and also learning about other subjects such as history, geography, religion and culture. He repays the family by secretly doing many of their household chores. Rashly, he reveals himself to the family but they are so horrified by his appearance that the Monster goes on the run again. He finds similar treatment from everyone he meets and becomes lonely and isolated. The Monster asks Victor to accept that he is responsible for his loneliness and misery and to make him a female companion to be his partner through life. Victor agrees in a desperate attempt to save the rest of his family from the Monster's revenge.