Three years after the second Thin Man entry, MGM brought back the property by popular demand with Another Thin Man. As ever, William Powell and Myrna Loy star as sophisticated sleuths Nick and Nora Charles, with the added filip of 8-month-old Nick Charles Jr. At the invitation of munitions manufacturer Colonel MacFay (C. Aubrey Smith), the Charleses spend a weekend at MacFay's Long Island estate. The Colonel is certain that his shady ex-business associate Phil Church (Sheldon Leonard) plans to do him harm, a prognostication that apparently comes true when murder rears its ugly head. Though he's promised to cut down on his drinking (after all, he's a daddy now), Nick spends an inordinate amount of time sorting out the clues and identifying the actual murderer-who, of course, is the least likely suspect (and in fact is played by an actor who seldom if ever harmed a fly in any other film). Adding to the merry mayhem is the Charleses' efforts to find a good baby-sitter, resulting in an onslaught of "help"-and additional babies!--courtesy of Nick's old Underworld cronies.
by Hal Erickson synopsis