When a friend of Peter's, Scott, attempts to perfect his fuel diffuser, four pilots are killed in four separate test flights. Peter steps in to determine if sabotage is involved and who on Scott's team may be responsible.
An important scientist decides to walk away from his ground breaking research just as he makes an important discovery. Brady must locate him and convince him to return to his work before foreign agents step in and steal his secrets.
Identical twin sister entertainers visit London as guests of the government. Brady becomes involved when one of the sisters disappears, and there seems to be a possibly spy scandal behind the disappearance.
A family is gunned down by terrorists in an Italian market. This sparks an investigation into how these people get the guns. The invisible man is tasked with breaking up the gun running activity.
The movement of a top secret rocket is compromised when of the scientists runs into gambling debts. The Invisible man realizes what might be happening and heads out on a desperate search for the missing rocket.
The invisible man is called in after a malfunction with a light sensitive bomb. Brady must somehow disarm the weapon before approaching darkness makes detonation inevitable.
Authorities become alarmed when they realize parts of an atomic bomb are found among the baggage from a crashed airliner. The Invisible man is tasked with finding out the source of the parts.