Summary- Proof of Forever

In the book "Proof of Forever" there are four main characters, Zoe, Tali, Joy, and Luce. These girls met at a summer camp and became best friends. They created many memories together, but once summer camp was over they all went their separate ways. Two years had passed and the 17 year old girls hadn't talked at all. One day, they decided meet up somewhere together. While at the reunion they wanted to recreate a picture and so they went into a photo booth to take a picture, they were then taken back to the summer they all met when they were 15. All four girls had to decide whether they wanted to repeat their past and have their friendship end right after camp, or change their past and have their future be different. The girls were confronted with challenges that made them think twice about their decision.