With Jared Harris starring, this miniseries about the 1986 meltdown should be gripping – but instead strands viewers in a bewildering cloud of unanswered questions

Chernobyl is like the 80s nuclear horror-drama Threads crossed with the disaster-movie classic The Towering Inferno – but delivers neither the shocking realism of one nor the schlocky flair of the other. Sky Atlantic’s five-part miniseries (co-produced with HBO) dramatises the 1986 disaster at the nuclear power station in what is now Ukraine.

It is – at least so far – a confusing sprawl for anyone not au fait with the details of the catastrophe itself, the workings of nuclear reactors generally, or with a very good eye for faces obscured by dust and smoke, and a knack for remembering complicated names drowned out by the sound of reactor cores exploding.

We begin with the suicide of nuclear physicist and state apparatchik Valery Legasov (Jared Harris) two years to the minute after the event, before heading back to 1986 as the good people of Pripyat note a distant glow on the horizon and – seconds later – are bracing themselves against a blast wave.

It is a bad sign when the first few minutes of a drama raise more extra-narrative questions than answers. Did the residents have no fear of what such a sight might mean? Why are they not running around trying to flee, as we would be? I am sure it is something to do with soothing, Communist-era propaganda and a well-trained, incurious mindset, but the writers need to sketch these things in a bit if they want viewers to be involved rather than instantly baffled by their story. This particular example becomes more pressing in a later scene, when we see the townspeople gazing in wonder at the distant fire and ionised blue air above it as their children play in the radioactive ash accumulating at their feet. I mean, I have questions.

The story is so unclear. At the plant, everyone is dressed indistinguishably in white uniforms, and any understanding of the situation the average viewer can glean is likely to come more from his or her knowledge of disaster-movie tropes than the action or dialogue here.

The man in charge, Anatoly Dyatlov (Paul Ritter, part of a uniformly excellent parade of performances fighting to make coherence out of chaos) is largely in denial. He insists, despite irradiated eyewitness accounts, that the core cannot have exploded. So he is not our hero. Maybe it’s going to be the nurse at the nearby hospital, who takes a squiz at the raging fire at the local nuclear power plant and wonders if they have any iodine tablets in stock, just in case.

“Why would we?” says the doctor cheerfully, silhouetted in front of the orange-blue glow of the raging fire at the local nuclear power plant.

We know things are Worse Than They Seem because a) the firemen who attend have increasingly uneasy expressions and keep keeling over and vomiting into bushes, b) everyone keeps insisting a core cannot explode as they pick their way over pieces of exploded core and c) Dyatlov refuses to countenance the suggestion from underlings that the radiation readings from the plant’s geiger counter-type thing are inaccurate because it has maxed out rather than taking a faithful record.

Amid the depicted and narrative chaos, which involves repeated “reveals” of the shattered core – it looks like a nuclear apocalypse in there! – we glean that opening the plant’s water valves will kill the men who do it, but will save the lives of millions. I assume that it will do this by averting something worse than a nuclear reactor’s core exploding and scattering itself over a wide area, but what this is I am not sure.

The two men in charge of the safety test that immediately preceded the disaster go down and start turning wheels and obliquely noting that, contrary to their claims in the control room, they did do something wrong during the test.

We should be engaged by the tragic flaws and nobility of all this by this point, but the story and characters have gone so uncorralled that it takes all your viewing energy just to keep it fractionally straight. I understand that it was a time of chaos – and very shortly after that, lies, half-truths and obfuscations that endangered lives and protected careers – but you can’t reflect that literally in a drama without incurring severe and pointless costs.

Things may improve over the coming weeks as the smoke clears, and I hope so. Chernobyl is a story that has everything, but at the moment, comrades, justice is not being done to it.