While riding on a commuter train, Bill Chalmers suddenly forgets who he is and where he is headed. His amnesia is accompanied first by a numbness of his hands and then later his legs. Eventually he is confined to a wheelchair and dependent on his family and a home nurse to care for him. Despite extensive testing and consultations with a variety of doctors, no one can make a definitive diagnosis of his illness.

Chalmers is subjected to many empirical treatments including antidepressants, steroids, plasmaphoresis, and psychotherapy, but his health continues to deteriorate and he loses his job. His wife and son become victims of his predicament. By the end of the story, Chalmers gains insight into his life and discovers that only his dignity still remains in his control.