All By Myself is another of Universal Pictures' "instant" musicals of the 1940s, built tenuously around the popular title song. Patric Knowles stars as a handsome but easily distracted doctor. Evelyn Ankers costars as Knowles' loyal clinic partner, who carries a torch for the oblivious Doc. When sultry nightclub singer Rosemary Lane shows up for treatment, Knowles is smitten, much to the discomfort of Ankers. She finally decides to chuck her dignity and restraint, using Lane's own "weapons" to win Knowles' affections.
by Hal Erickson synopsis