On a June day in 1950, Trudy Thompson receives a postcard from her best friend begging her to come to Cody, Wyoming. Naturally, Trudy boards the first train West. 

    On the same day, British agent, Charles Littleton, picks up the trail of a Russian agent in Washington D.C. and pursues his quarry across the United States to Cody, Wyoming and Yellowstone National Park. 

    With the help of a dog named Bandit, Charles and Trudy match wits as they both try to prevent treasonous scientists from selling secrets to the Russians.