The Foster Brothers, two rich conmen who claim to be spiritualists, try to convince Jeannie that Marty is haunting her as a poltergeist, by using electronic equipment to smash objects in her apartment. Holding her trust, they then recruit her to leave Randall and Hopkirk and work for them, earning £75-£100 to ensure that widows like her use their medium service.
Attempting to lure Jeannie back, Jeff pays an actress friend Laura Watson a scraped £250 to play the role of a client looking for a lost son. However, the actress shortchanges Jeff by only handing £25 over to Jeannie, who in turn introduces her to the Fosters. While there, they reveal that they intend to kill Laura, the only difference between her and their previous victims being that they're telling her in advance, so that she'll know they'll try to reach her on the "other side". Genuinely interested in being mediums, they also ask her to contact Marty Hopkirk after her death, as a reward for his widow Jeannie.
Using Marty's help Jeff uncovers their plans, whereby they decide to kill both Jeff and Jeannie using their equipment. Marty teleports to a nearby electricity power station and overloads the grid, blacking out the whole of southern England, including the Fosters' home. With Jeff calling the police, the brothers are arrested, and Jeff finds Laura Watson hiding in the back of his car, covered in only newspapers after having swum to safety while the plot developed.
Although the 3rd episode in the series, All Work and No Pay was the 12th episode to be shot, filmed between November and December 1968.
A finished print was completed by mid-May 1969. It is listed as episode 16 in ITC literature.