The Jackson are a nice middle aged English couple. Their best friends are their Canadian neighbors, the Krogers. All is blissful in their world until a detective from Scotland Yard asks to use their house as an observation station to try and foil a Soviet spy ring operating in the area. The Jacksons become more and more put out as Scotland Yard's demands on them increase. They are really put to the test when the detective reveals that the spies are the Krogers and he asks them to help set a trap. Should they betray their friends?