Starting a new book in series of  life, not just a new chapter. New sequence of events, settings, new suppprting characters,  and advancement towards the ultimate goal, however same main characters, same theme. The characters are becoming more developed more loved and important to the story. Background stories are becoming known and give light to the over all story. Not a new chapter, but a new book. The 2nd is always so good, but not possible without the 1st.