The Tomorrow Code by Brian Falkner was truly a roller coaster read. Tane and Rebecca are two friends just hanging out one night when the subject of time travel comes up.
Rebecca is a true genius in science and math and attempts to explain time travel theories to Tane. They try to figure out time travel on their computer when they suddenly get a message that seems to be from the future. It has the winning numbers for the lottery the next day. They are rich!Tane and Rebecca are rich but troubled.  Who is sending the messages?  Why?  Soon they start to receive more messages and they discover that the messages are from themselves. Tane and Rebecca are sending messages back in time.  Something has gone terribly wrong in the future and they now have to prevent it from happening.  They start to follow the cryptic messages and realize that survival of the human race depends on Rebecca and Tane.
Will they be able to save us all?
The Tomorrow Code by Brian Falkner was a tense and thrilling read. Give to your most reluctant reader.