Department S

Department S was a 1969-1970 British television series about three secret agents who work for a special department of Interpol and are tasked with solving crimes that the regular Interpol agents cannot solve. It starred Peter Wyngarde, Joel Fabiani, and Rosemary Nichols.

A Ticket to Nowhere (Season 1, Episode 8)
Gerald Blaine, clad only in his pajamas, wanders onto an airport runway and is killed by an incoming jet. Jason (Wyngarde) interviews the dead man's niece Susan (Bridget Brice), who tells him that her uncle was worried about making trips every weekend but not remembering anything about them. Meanwhile, Stewart (Fabiani) and Annabelle (Nichols) learn that Franz Drieker (Michael Gwynn), a scientist working on an advanced form of brainwashing, has disappeared, and that every member of his research team has no memory of him or the project.

Jason escorts Susan back to her apartment, where they are ambushed by two thugs; Jason fights them off while Susan runs to safety. The next day, Jason runs into Susan and discovers that she has no memory of him, her uncle's airport death, or the fight in her apartment. That evening, Susan goes into a trance and makes a report to an unknown party, then phones Jason and tells him that she has suddenly remembered that her uncle used to visit a country club every weekend. Jason manages to book a room at the club to investigate further.

The next morning, Annabelle discovers that both Jason and Stewart have no memory of the Drieker case. Realizing that they'll get nowhere if everyone keeps getting their memories erased, the three agents decide to let Jason be captured again. Jason lets Blaine's assistant Lisa (Fiona Lewis) drive him to the country club, where he is drugged and subjected to the brainwashing procedure by Drieker. Drieker programs Jason to walk out in front of a plane as well, but Annabelle and Stewart save the day.