Admittedly, I haven’t listened to any others in this series. That makes this a true stand alone for me. Some back story on others would be helpful, but it wasn’t necessary to enjoy this one. I appreciate that the 2 main characters are a little older. You can only hear about college-aged kids so many times. I liked trying to figure out the mystery of the last and anxious to find out where the future is going to lead. The story moved along quickly and I’ll need to look more into more in this series.