A tenant reports an awful smell coming from her neighbour’s apartment and Jaschek is caught in an elevator.

Of the previous episode, I expressed a concern that the story wasn’t unreeling as quickly as I’d have liked. Thankfully, this grim German-language horror thriller has opened up some new plot threads while also dripping in some exposition, like the black viscous goo that’s glooping out of the pipework.

Juri is still estranged from his dad, sleeping with the drug dealers rather than staying in the peculiar new, familial relationship. When confronted by his father, he stands resolute, refusing to return. Jaschek also has the grim task of investigating the smell coming from Mrs Loeber’s apartment, only to find her desiccated corpse.

There’s a large hole in the victim’s wall, coated in the black mould that would seem to be the root of the residents’ problems. The organic liquid is traded with drug dealers, consumed by a clairvoyant, and potentially causing illness in some of the residents. What is this mysterious material?

Elsewhere, young student Loan (Andrea Guo) is the focus of our attention, posing nude for a photographer neighbour and suggesting that he kidnaps her so that they can skip the country with her miserly father’s fortunes. But the most significant event in this hour is Juri’s attempted rescue of his father, trapped in an elevator, the fallout of which will no doubt be revealed next time.

Verdict: A strong fourth episode that takes us to the series’ mid-point, while still keeping most of its cards very close to its chest. 8/10

Nick Joy