An earnest rural melodrama set among Norwegian immigrants in Wisconsin, Our Vines Have Tender Grapes is a slightly updated version of George Victor Martin's 1940 novel. Edward G. Robinson stars as Martinius Jacobson, a farmer devoted to his wife Bruna (Agnes Moorehead) and precocious seven-year-old daughter Selma (Margaret O'Brien), whom he lovingly calls "Jente Mi." Along with her freckle-faced five-year-old cousin, Arnold (Jackie "Butch" Jenkins), Selma lives a carefree, joyous life, which is only temporarily clouded by the sudden death of Ingeborg Jensen (Dorothy Morris), an emotionally disturbed young women whose stern father (Charles Middleton) had refused to let her attend school despite the pleas of newly arrived schoolmarm Viola Johnson (Frances Gifford). The latter is quietly falling in love with Nels Halvorson (James Craig), the town newspaper editor, but cannot envision herself as a rural wife. She changes her mind when, inspired by young Selma, the entire town of Fuller Junction come to the aid of Bjorn Bjornson (Morris Carnovsky), who has lost his livestock when lightning struck a newly erected barn. When Selma generously donates her pet calf to the impoverished farmer, the townspeople in general, and Martinius in particular, follow suit, prompting Viola to reconsider her harsh views of country life and retract her letter of resignation to the school board.
