Complex sentence: In a surprise ending, when Sarah returns to England and visits her publisher's office, Julie also shows up in the office; however, the girl in England is literally a different person from the girl that Sarah lived with in France.
Split into simpler sentences: In a surprise ending, when Sarah returns to England and visits her publisher's office, Julie also shows up in the office. However, the girl in England is literally a different person from the girl that Sarah lived with in France.