"That Girl" isn't Marlo Thomas, but instead heiress Jeanne Hudson (Barbara Kent). Someone has tried to murder Jeanne with a bow and arrow, obliging the Hudson family to hire detective Larry (Robert Allen) as a bodyguard. As was typical in films of this nature, Larry is saddled with a "helpful" secretary named Helen (Florence Rice), who fancies herself an ace gumshoe. But it's the family dog Lobo who sniffs out the villain, leaving Larry to explain the miscreant's motives. Barbara Kent, a second-echelon heroine of the silent era (she co-starred twice with Harold Lloyd), made one of her last screen appearances in Guard That Girl. ~ Hal Erickson, Rovi