Finishing out her Paramount Pictures contract, opera star Gladys Swarthout sings not a single note in the tense little thriller Ambush. After pulling off a bank robbery, a clever gang of thieves squirrels itself away in a rural hideout. Complicating matters is the unexpected arrival of Jane Hartman (Swarthout), the sister of one of the crooks. Hoping to keep her brother and herself alive, Jane is obliged to coerce an honest truck driver named Tony Andrews (Lloyd Nolan) into helping the fugitives escape. Ambush is distinguished by the bravura performance of Ernest Truex, usually cast in milquetoast roles, as the brilliant but deadly "brains" of the outlaw gang.