MI5 needs a new electronics expert, and Peter Chapman is the one they want. After unexpectedly losing his lecturing job at the polytechnic, Peter is left with little option but to accept MI5's offer, and become Piglet.

Piglet is tricked into temporarily housing a recently defected electronics specialist. Agents are sent to kidnap and return her. However, they take Piglet's wife instead.

The team is assigned to monitor a couple suspected of transmitting information to East Germany. But are they watching the right people?

Piglet is the victim of mistaken identity, with potentially fatal consequences.

Piglet must use all his espionage skills to infiltrate an activist group and plant bugs.

The French have developed a top secret device for use on their military aircraft. During a test flight, the plane crashes. Everybody wants to get their hands on the device when the debris is recovered.

Sir Desmond wants to make budget cuts by amalgamating MI5, MI6 and other agencies. Piglet and his colleagues use their espionage skills to try to find the skeletons which might persuade Sir Desmond to reconsider.