Covert

In a covert listing station an operative picks up a telephone conversation between someone he suspects is an agent and someone called mother. He follows their communication and intercepts another message about cakes and candles. However has he stumbled upon a plot of major importance or just something innocent? In a covert listing station an operative picks up a telephone conversation between someone he suspects is an agent and someone called mother. He follows their communication and intercepts another message about cakes and candles. However has he stumbled upon a plot of major importance or just something innocent?