Imagine if one of the highly acclaimed US series, say “House of Cards”, only aired a new episode every six months. The viewer would have a lot of trouble following the plot. Well, Frank Underwood and his wife Claire – you could probably still remember them. But why did this journalist have to die again – and what is this ominous stripper all about?

It’s a bit like that with “Ätzend”, the second mission of the Berlin “Tatort” team, which was first broadcast in November 2015. You quickly get the feeling that you don’t have all the information ready to fully understand the episode. Because large parts of the plot go back to the first episode and to events that happened even earlier.

The beginning couldn’t be more confusing: Inspector Karow (Mark Waschke) is sitting in a café with a man who is not presented in detail. It’s about the death of Karow’s partner Maihack, a bullet and a “classified report”. In a second scene, the investigator talks to a psychologist – this is also about a police operation that also happened in the past. So far so confusing.

But the episode gets even cruder: a dialogue follows between Karow and his colleague Nina Rubin (Meret Becker), which revolves around the first case that has already been completed. The film was broadcast in March 2015.

It takes ten minutes for the episode to arrive in the present: two bodies are found at a construction site: one in an acid barrel, one buried in the ground. As it turns out, these are two separate crimes. One has to do with Karow’s dark past. How exactly – that is not cleared up until the end.

In return, the second strand can claim to take up at least one socially relevant topic: It is about the fate of refugees living in Germany.

The other case, however, remains unclear. For this it goes Karow on the collar. He is arrested at the end – he is said to have killed his partner. Someone in the ranks of the police is working against him and is spreading rumors that he is said to have had an affair with his colleague’s wife. If that’s true? Doubts are aroused, at least in the viewer, because apparently the investigator seems to be more into men.

The fact that the mostly conventionally told “crime scene” wants to break out of the tight 90-minute corset is commendable. And as the Dortmund “crime scene” with Jörg Hartmann shows, it can work for a while. But only if you don’t overload the horizontal narrative thread.

The Berlin “crime scene” already collapses in the second episode (book: Stephan Wagner and Mark Monheim, director: Dror Zahavi) under the complexity of the information that the viewer has to keep ready.

“What do this ball and Bielefeld have in common?” Karow’s ominous interlocutor asks at the beginning. “Both don’t exist,” he replies. Viewers searching for the common thread here might come to a similar conclusion.

The “Tatort” episode “Ätzend” was first broadcast on November 15, 2015. ARD repeats the case on Friday, August 25 at 10:20 p.m.