1958. England during the Cold War. The Russian Jewish émigré, inventor and designer of hearing aids Samuel Petrukhin has clients such as Sir Winston Churchill. It doesn't take long before he is approached by MI5 who want him to demonstrate his knowledge. It soon becomes apparent that MI5 is not interested in his knowledge of hearing aids. He must instead inquire about his charming new friends Kathleen and her husband Richard Shaw. Through Shaw, Samuel is also introduced to the impressive Lord Arthur Wallington. Little by little, Samuel's life becomes more complex as a result of this mission. Because who can he trust and what consequences does this mission have for his wife Miriam and their children Hannah and Sasha?