Tammy Tucker, a young woman from Mississippi, becomes a nurse's aide after dropping out of college. She moves to California and starts working in a hospital where she meets Dr. Mark Cheswick, a young surgeon who is engaged to the hospital's administrator's daughter, Deborah. Tammy is immediately attracted to Dr. Cheswick and causes romantic commotion in his life.
Meanwhile, Tammy is assigned to care for an old rich woman, Mrs. Farnsworth, who is dying of cancer. Tammy develops a close relationship with Mrs. Farnsworth and eventually becomes her confidante and friend.
As Tammy and Dr. Cheswick spend more time together, their attraction grows stronger. However, Dr. Cheswick is torn between his feelings for Tammy and his loyalty to Deborah. Tammy, on the other hand, is unsure if she is ready to settle down with someone like Dr. Cheswick.
In the end, Tammy chooses to leave California and go back home to Mississippi. However, Dr. Cheswick realizes he is in love with her and follows her to Mississippi. They kiss and embrace, and it is implied that they will start a romantic relationship.
Overall, Tammy and the Doctor is a heartwarming romantic comedy that explores themes of love, loyalty, and self-discovery.