Henry is a neurotic physicist with a deep fear of public speaking. Ginny is a perky but brilliant southern belle. They work together at the Fermilab National Accelerator Laboratory in Batavia, Illinois. Felix, Henry's friend and a janitor at Fermilab, is convinced that Ginny and Henry are destined for each other, even though Ginny has just eloped with her fiancé. Felix has memories of Ginny and Henry falling in love. The only problem is the memories never happened. Ginny is happily married. Ginny and Henry team up to work on a paper for an important Physics prize. Ginny falls in love with the work and Henry falls in love with Ginny. Despite their feelings, Ginny returns home with her husband at the end of her internship. From this point on, the story travels in reverse. As each scene repeats itself, Ginny and Henry's future changes their past. When the story returns to the beginning, Ginny, sensing she wants something more from her life, chooses not to marry her fiancé. She then meets Henry, now for the first time, and begins a new future with him.