Often mistakenly identified as a sequel to My Friend Flicka, Thunder in the Valley actually has more in common with the Lassie saga. Lon McAllister plays the son of truculent Scottish sheepherder Edmund Gwenn. Though he has no time for people, Gwenn is quite fond of his collie dog. Partly as a means of defying his intractible father, McAllister raises his own dog and beats Gwenn at an annual contest. Father and son are brought closer together when Gwenn is forced to do away with his collie, who has gone mad. Breathtakingly photographed in Technicolor (those nocturnal Highlands scenes are terrific!), Thunder in the Valley is based on the popular Alfred Ollivant novel Bob, Son of Battle. Lending excellent support to stars Gwenn and McAllister are Peggy Ann Garner and Reginald Owen; reportedly, perennial Laurel and Hardy foil James Finlayson also appears in the role of a judge.
by Hal Erickson synopsis