King of the gimmicks William Castle makes another trademark cameo as the victim of a gruesome car crash at the start of his, atypically gimmick free, juvenile thriller Let’s Kill Uncle. Newly orphaned twelve year old Barnaby Harrison (Pat Cardi) stands to inherit five million dollars, but is trapped on a deadly island in the care of his malevolent uncle Major Kevin Harrison (Nigel Green). A former British intelligence commander and author of the definitive guide to killing people, Uncle Kevin gleefully admits his intention to murder young Barnaby and uses every trick in his book - sharks, poison mushrooms, fire and tarantulas - to make it look like an accident. Barnaby’s policeman guardian Sgt. Frank Travis (Robert Pickering), already less than happy babysitting the bothersome brat, is too busy romancing kindly Justine (Linda Lawson) to believe his tall tales, but the boy finds an ally in her niece Chrissie (Mary Badham), an equally precocious young girl visiting the island. Together they try to outwit uncle and give him a taste of his own medicine.
Children always made up the lion’s share of William Castle’s audience anyway and he in turn had a knack for tapping their playfully malevolent side. Young viewers delighted in watching characters in Castle’s horror movies getting spooked out of their wits, in a manner uncomfortably similar to seeing bugs tortured under a magnifying glass. Let’s Kill Uncle spins a “boy who cried wolf” scenario and uniquely for the period, establishes its child heroes as squabbling brats prone to pranks and morbid fantasies about death and killing. This approach may grate on some nerves, but making the youngsters less than perfect angels adds a ring of believability to their interaction, as they are drawn together more by necessity than attraction. While Barnaby is drawn a rather odious moppet, Chrissie is given a little more depth as a troubled trailer park kid, cruelly abandoned by her divorced parents. Having given one of the greatest child performances in cinema in To Kill a Mockingbird (1962), Mary Badham - whose famous brother John Badham served as casting director here, by no coincidence - had her last screen role in Castle’s film, though she recently broke her self-imposed retirement with Our Very Own (2005).
The film was adapted from a novel by Rohan O’Grady, which was the pen name adopted by Canadian author June Skinner. Between raising three children in a quiet suburb in West Vancouver, Skinner wrote four books - O’Houlihan’s Jest (1961), Pippin’s Journal, or Rosemary is For Remembrance (1962), Let’s Kill Uncle (1963), and Bleak November (1970), writing her fifth and final novel The May-Spoon (1981) under another pseudonym: A. Carleon - notable for their gothic sensibility and more physical violence than was common for young person’s literature. As played by a delightfully dry Nigel Green, Uncle Kevin comes across like an overgrown kid who shares Barnaby’s obsession with the macabre and cheerfully advises him to think of their struggle “as a kind of game.” However, Castle’s thrillers were always wafer thin on a psychological level, so it is no surprise he fails to explore the disturbing undertones of kids caught in a cat-and-mouse murder plot in any meaningful way. Sunny photography by Harold Lipstein and a jolly score from Herman Stein further cramp Castle’s already flat attempts at suspense, and leave this looking like a particularly perverse Disney movie. At its best the film has a streak of cartoonish black humour, but as with much of Castle’s, beneath the larky bonhomie lies an unpalatably cynical view of human nature. There are loose ends (e.g. Aunt Justine’s devotion to her late boyfriend and a seemingly benevolent supporting character who fakes their own death) while the bizarrely flippant ending is both a copout and genuinely perverse as Uncle Kevin tries to write this off as a life lesson for the kids. One unsettling implication being, Barnaby looks likely to grow up the same way.