Fatal Convergence by Bryan Davis

Book 3 of Time Echoes Trilogy

Summary:

In the final installment in the Time Echoes Trilogy, the three Earths are ready to collide. As they close in, Fatal Convergence begins taking place–the deaths of duplicates on two of the three worlds. When Nathan learns one way to stop the tragedy, by killing three innocent people who represent the three worlds, he balks, intent on finding another solution. When Kelly is absorbed into a nightmare world, Nathan must search for her, not only because of their friendship but also because her talents could be the key to saving everyone. With billions of lives hanging in the balance, failure is not an option.

Opening Lines: 

Cerulean and I walked through Kelly's dream--a dark cemetery with tombstones protruding from the ground at odd angles. The air grew frigid, making me glad for the gray Iowa sweatshirt I had borrowed from Nathan of Earth Blue. Since he had suffered a tragic death, he no longer needed it.