Doug and Judy have both had a secret power all their life. Judy can see every possible future, branching out from each moment like infinite trees. Doug can also see the future, but for him, it's a single, locked-in, inexorable sequence of foreordained events. They can't both be right, but over and over again, they are.
Obviously these are the last two people in the world who should date. So, naturally, they do.
A finalist for both the Nebula Award and the Hugo Award.