Richard Cross is a middle age college professor in Southern California. His alarm clock wakes him up at exactly 6:30 every morning. He jogs to the rhythm of music on the same radio station every morning. Because they play different songs he jogs to the rhythm and he can’t understand why he travels the same distance and ends up back home at about the same time.

 

Every day he stops at the same intersection. The same homeless veteran cleans his windshield and Richard always sees the same speeding red semi-truck almost crash into them. The one morning he decides to stop for coffee the red semi-truck crashes into his car and kills the homeless veteran. 

 

While going through his father’s papers after he committed suicide, he discovers his father was working with a professor Angstrom on the same theory he is working on that everything in our reality might just be a simulation.

 

One of his student’s named Sarah is also studying Angstrom’s theories.  Believing Angstrom is teaching at an institution in Oregon they travel there hoping to get some answers. While paying for gas Richard looks up and he sees the same red semi-truck crash into the SUV he rented. He storms out and sees everything now appears normal. When they pull out of the station a Greyhound bus barely misses crashing into them. When they arrive at the institution, they discover Loretta Angstrom is really just a metal patient there.

On the way back to California they discover a storm has closed the main highway. They end up sharing the last hotel room available for miles. Their relationship turns romantic. The next morning, they stop at the same gas station and the same Greyhound bus almost runs into them again.

 

Back in California Sarah crosses a busy street. Loretta Angstrom who escaped from the mental institution, grabs her, and tells her she can save Richard. Sarah struggles to get away. She falls backward and  hits her head on a fire hydrant.

 

The same Greyhound bus in Oregon runs over and seriously injures Doctor Angstrom. Richard runs over to Sarah's lifeless body and cradles her in his arms. After Richard recovers from a stay in a mental institution, we see him with his wife and son as if none of this has happened.

 

He is teaching a class in the same lecture hall we saw at the beginning of the movie. This time Sarah’s desk is unoccupied, yet her jacket hangs on the seat that she occupied in the beginning of the movie. Like an Alfred Hitchcock movie we are not sure if this was just a simulation that was playing out in Richard’s head or was it real?