When Richard Logan, the partner in a safe making firm, is found unconscious, on an old deserted bomb site, he finds that he has no recollection of the last three weeks. Then he discovers that the private detective, hired by his wife, has been found murdered, and a safe that his firm installed in a large country house, has been cleverly opened, and the contents are missing. So with the help of his wife, he sets out to uncover the truth.

An international criminal arrives in London, and a detective is anxious to pin something on him for some unprovable murders of former lovers. The villain starts to suspect servants and henchmen of being a police spy known as "Number Six".

A man travels to Istanbul to try and prevent a revolution.

American scientist Dr. Frank Smith is brought to Britain to help the C.I.A. There is a defecting East block scientist they want him to debrief. The commies are less than amused and set Dr. Smith up for a murder.