What is the main conflict of turnabout by haddix?

I think the conflict is understanding one's true identity. As adopted children, the two boys have the normal questions, but as the mysterious letters arrive, the boys have additional questions. We leave the boys as they are still trying to find out their identities. Additionally, survival is explored as the boys and sister try to survive the time travel and abduction. Love is also evident in the love between brother and sister and the discovery of its strength.
The primary conflict is the Jonah and Chip's search for their identities.