Since my novel is set in Nazi Germany and not Disney World, any continuation of the story started by Sophie needs to be told by a different protagonist. Rennie has picked up where Sophie left off and I'm writing again, but now through Rennie's eyes.
As a writer, I couldn't remember any series or sequels where different protagonists take up the cause so to speak and carry on to face more pieces of the overarching problem. So I asked other writers. A member of one of my Yahoo groups suggested two books by Gayle Forman, If I Stay, and Where She Went. I can't say enough good things about If I Stay- it's written with an amazing combination of eloquence and brevity. It's told in first person, and for much of the book, Mia the protagonist lies in a coma and tells the story from her out-of-body experience. I just requested Where She Went from the library, and the blurb says the story picks up from her awakening and is told through the eyes of her boyfriend Adam. I can't wait to read it.
Nice to know an accomplished writer can have two books with one story and different protagonists. Makes me think my ideas have a chance, too.