Victor Sebastian goes to Switzerland to try to obtain a manuscript from a former agent who has written about his past intelligence work, for several countries, and intends to publish it. But other people are after the manuscript too.
Sebastian goes to Mexico to buy a list of names of opponents of the Communist regime who still live behind the Iron Curtain and might be willing to help the US. But he is double crossed and the list's owner takes off with the money.
Victor Sebastian acts as a double agent when he investigates a leak of confidential information for the Russian Communist Party, which has a spy network in America. The person who is the source of the leak proves to be keen to defect.