In their never-ending efforts to create a movie series to match the success of "The Thin Man," MGM came up with the fast-paced programmer Mrs. O'Malley and Mr. Malone. Based on characters created by Craig Rice, the film stars James Whitmore as lawyer and part-time sleuth John J. Malone (this character had previously appeared in several other films, as well as the radio series The Amazing Mr. Malone). In his efforts to track down an embezzler, Mr. Malone boards a train heading for New York. Meanwhile, Mrs. Hattie O'Malley (Marjorie Main), a raucous widow from Montana, is also travelling to New York to claim her prize money from a radio contest. During the journey eastward, the man whom Malone is seeking ends up dead. Thanks to Mrs. O'Malley's well-intentioned interference, Malone ends up being accused of murder. How this mismatched pair manages to solve the mystery and save their own hides is good for several laughs. Mrs. O'Malley and Mr. Malone didn't result in a series, though James Whitmore and Marjorie Main make a surprisingly copacetic screen team.
by Hal Erickson synopsis