Zach and Anna's story was supposed to be a short 40 chapter stand alone book, and ended up being a long, long one with a sequel and many alternate universe theories and bonus chapters and a mass following and liking towards them... not that I'm complaining.
However, like many other journeys, Zach and Anna's too had to come to an end, but that doesn't mean this is the last you have seen of them. Their book mentions many other characters, some of which have their own books, and like these characters play a role in HIS and Always HIS, Zach and Anna play side characters in many other books.
Some of the other main characters are:
Sia and Cole
Justin and Tara
Ruth and Jay
Daisy and Caleb
Natasha and Niklaus
And, hopefully soon, we will also have books about the second generation, but to
