This is based on 2 kids who are getting mysterious letters from somebody saying “You are one of them”. They then tried to figure out who had sent them. They finally got somebody who had witnessed something they were talking about. So one day they visited that person at the library and their lives changed before their eyes as they realized time-travel was real. There are 3 main characters, Johan, Katharine (not one of the 33 kids), and Chip who are the ones who got interested in solving the mystery to the end. They then went to a conventional for adopted kids and finally realized the most amazing thing. Somebody may like this if they like historical fiction or science fiction. it is for both boys and girls and has a bit mystery.