In 2023, two former BND heads penned a joint article in a German newspaper, describing the agency as a “toothless watchdog with a muzzle and an iron chain”. Other spy services didn’t trust it with information because it was subject to a “sprawling control-bureaucracy” of at least seven external oversight bodies.

The strict regulation is in part a response to unease over the BND’s predecessor, the Gehlen organisation, set up by Major General Reinhard Gehlen, a Nazi-era military intelligence officer who worked for the Americans post-war. He employed numerous ex-Gestapo and SS officers, on the basis that they were only people capable of dealing with subversion from Communist east Germany.

Thanks to the modern restrictions, the BND often focuses less on active 007-style field missions and more on information analysis. Which is not a template for exciting spy drama, unless one has a particular appreciation for watchful line managers and diligent parliamentary oversight committees.

“It was a bit of a learning curve,” Coates admits. “For example, the BND aren’t allowed to spy on German citizens – so that was a difficulty.”

Coates got around this by centring the action around two former, rather than serving, BND agents – Simon Schäfer and his wife Meret. The middle-aged couple run a BND-authorised safe house in Berlin, where spooks who get into trouble on missions can seek sanctuary. Their semi-retirement is then disrupted by the arrival of a wounded hitman, who claims to be a “friendly”, but who has sinister intentions. It’s all linked to Russian agent Josef Koleev, whom the Schäfers have history with from an operation in Belarus 16 years before. The real secrets in the drama that unfolds, though, are personal ones between the Schäfers themselves and their 16-year-old daughter, who is not quite whom she appears.

As former agents, the Schäfers also have rather more leeway to go rogue, getting involved in surveillance operations and car chases that might otherwise fail the average BND risk assessment form. True to his soap-writing roots, Coates also concentrates on how the events affect the Schäfers as a family – hence the title Unfamiliar, which plays on the words “family” and “liar”.