As Melanie prepares to embark on her apparently suicidal mission, tensions remain high both on and between Snowpiercer and Big Alice, not helped by Wilford’s determination to foster conflict wherever he can.

I’ve said it before but it bears repeating – among a crowded cast full of talent, Rowan Blanchard as Alex is really the standout of the show this season. Her character’s complex set of emotions – anger at her mother for having ‘abandoned’ her, loyalty to Wilford for having ‘saved’ her – are only the start of the story. She’s also fiercely intelligent – enough to know when Wilford is manipulating her equally as much as to know when her mother is trying to get past her guard. In this episode, it’s apparent that her feelings towards her mother are starting to thaw from the cold rage she first felt, but that doesn’t mean she’s all the way there yet, and Blanchard nails that tricky balance in every single scene.

Aside from watching her and Jennifer Connolly’s masterclass in character acting though, there’s plenty else to enjoy here. Sean Bean is having the time of his life playing Wilford, the maniacal yet brilliant engineer who plays with the emotions of those around and ‘beneath’ him seemingly for sport, although Bennett has another theory about that – one which rings increasingly true the more we see of the man and his gleeful cruelty.

Elsewhere, Layton’s problems continue to mount. If dealing with Wilford’s political manoeuvres wasn’t difficult enough, there’s rumblings of discontent throughout the train – the Tailees are starting to doubt whether he’s still one of them, the other classes’ resentment of the new order is only amplified by the return of their ‘saviour’ and the whole train is a powder keg of emotion it’s down to him to try to keep in check. And that’s without his complex private life. Josie isn’t the forgiving type, and Melanie isn’t her favourite person for obvious reasons. That Layton is working with her seems to bother her a whole lot less than his having a child with Zarah, and it’s clear that even when things have resolved with Wilford one way or the other, Layton’s life will continue to be complicated.

And there’s Bess, trying her best to get into her new role as Train Detective and bring to justice whoever attacked and disfigured Lights. She has what seems a pretty solid theory as to who might be behind it but a confrontation with that group suggests she might be wrong, while revealing another thing that she and Layton may have to concern themselves with in the future.

It all rolls along as mercilessly and inevitably as the train itself as they head for the ‘breakneck turn’ where they can drop Melanie off at the research station, the screws turning remorselessly on various characters as the tension ratchets up minute by passing minute. Honestly, it’s hard not to envy Mel her trip into near certain freezing oblivion – at least she’ll get to avoid all the politics for a month…

Verdict: Never anything less than crushingly tense with scenes that put the viewer through one emotional wringer after the next. Brilliant. 9/10

Greg D. Smith