Father Unwin and Matthew are put onto the case when the Ambassador of Dreisenberg attempts to smuggle a stolen mini-computer out of the country.

Father Unwin and Matthew are sent to investigate the sabotage of several desalination plants with the help of Agent Blake.

Father Unwin and Matthew are put on the case when enemy spy George Grey escapes from a maximum security prison and disappears over the estate of Sir Humphrey Barton.

Father Unwin and Matthew are sent to plug a security leak for a top-secret project.

Father Unwin is assigned to accompany a bullion train after an attempted robbery.

Father Unwin and Matthew are puzzled when they are assigned to investigate a security leak regarding an early warning satellite.