An eccentric inventor disappears and there’s no shortage of suspects, from his tawdry girlfriend to his ex-wife’s deadbeat husband. There’s a Dashiell Hammett mystery at the bottom of this movie, but it’s inconsequential—what this dishy lark is really about is the enthralling banter between the most debonair, comfortably droll, mutually secure movie couple of all time, Nick and Nora Charles (William Powell and, in a career-making turn, the delectable Myrna Loy). The Thin Man is an anniversary movie for those who don’t want romance and sentiment; these two are past that stage, and instead they make marriage look fun, from Loy’s dismissive nose shrug to Powell, hungover, shooting at Christmas ornaments while reclined on the sofa (“Best Christmas present I ever got!”) to fur-trimmed dressing gowns and flowing martinis. Movies haven’t dared to portray this kind of grown-up relationship too often, and this one made stars of its leads. But the secret of it is that this is romance, too—there are no moony gazes or clinches, but it’s evident to the blind that the Charleses, however they may snipe and gripe, are terribly, splendidly in love, and that they enjoy each other like sunny days.