The Eternity Ring

S8 E1: 16 July, 1945. A military convoy arrives in the New Mexico desert carrying Professor Michael Fraser, a British nuclear scientist, and his wife, Helen Fraser. Another scientist, Max Hoffman, is waiting for them, and he takes them into a bunker where they watch the explosion of the first nuclear bomb together. One year later, a cypher clerk, Aleksei Gorin, steals secrets from the Soviet Embassy in London. He is chased by NKVD agents but manages to escape.