At the outbreak of WWII the British realise they can't prevent the invasion of the Channel Islands. However, someone realises that a prize cow is on the islands and the Nazis mustn't get hold of her. This is the intrepid story of the cow-napping from under the noses of the Nazis.

Bedelia Carrington is living happily, it appears, in Monte Carlo with her husband Charlie Carrington. But a cultivated young artist, Ben Chaney, begins probing into her past with curious concern. Chaney, who is really a detective, learns that Bedelia's obsession for money has led her, in the past, to husband-poisoning for the insurance money.