DUBAI: At first, it seems like “The Eternaut” is going to be a climate-crisis-focused piece. It’s summer and Buenos Aires is boiling in more ways than one — demonstrations against government incompetence rage on the streets while power cuts only increase the oppressive heat felt by residents. Then a sudden fall of deadly radioactive snow kills hundreds of thousands instantly.

The snow continues to fall as survivors quickly work out that to venture outside without full body cover and masks is to guarantee death. A small group of middle-aged friends were enjoying their regular poker night when the snow began to fall, and it is on them that the series centers — particularly Juan Salvo, a veteran of the war between Argentina and the UK over the Falkland Islands (or the Malvinas, as they’re called in Argentina).

There are many other survivors, including people in the neighborhood they’ve known for years, and the show does a fine job of exploring the escalating paranoia as people accustom themselves to their new reality and realize that their acquaintances are potentially as deadly as the snow. There are echoes of the source material’s political edge too, as the line between neighbor and enemy blurs.

Juan (a convincingly grizzled Ricardo Darin) manages to find his ex-wife, but their daughter, Clara, is missing — she was at a friend’s house when the snowstorm started. Much of the first two episodes is taken up with Juan’s unsuccessful search for her. The starkly beautiful cinematography is often breathtaking, and the claustrophobia is palpable, both in the houses of the survivors and in the suits they must wear to go anywhere.

Halfway through the six episodes, though, there’s a grinding shift of gears. The apocalypse, it tuns out, was actually the result of an alien invasion, the first wave of which involves giant bugs. Juan’s super-smart friend Tano correctly predicts that the bugs are controlled by something more sinister.

That sudden shift means the enjoyable slow-burn grittiness of the opening episodes is lost, as the show becomes more CGI-action-based. It’s still gripping, but what had promised to be a unique standout fades into something far more generic.