The following piece is bristling with devastating spoilers, so only continue if you’ve already seen it or don’t intend to.

Opera is rubbish. Space opera is only mildly better. No-one turns out to be anyone’s father in Serenity; royalty are not involved. There isn’t even a struggle between good and evil, and it has characters instead of charicatures. That, vaguely, is why it’s better than Star Wars.

I’m sorry, I love sci-fi, I happily endure the trashy bits and the awful acting, and lightsabers are awesome; but ultimately, I like things that are actually good. I prefer to genuinely enjoy something than keep my tongue in my cheek. Specifically, it was when I was crying, laughing and biting my fist at the same time that I decided Serenity is better than everything else.

The crying bit was the only one that owed itself partially to the preceding series – no-one could watch the film and not like Wash by that point, but for Firefly fans he’s an old friend, and his loss is absolutely wrenching; all the more so for being completely unexpected (sorry, people who ignore spoiler warnings). Usually when a character dies on-screen I’m praying we’re not going to be insulted by some flimsy device to bring them back or pretend it didn’t happen – revealing it to be a cheap trick to toy with an emotional involvement it never earned in the first place. This was the first time I was hoping for one of those, however dumb – it was the first time I’ve cared more about the character than the film itself.

Probably the most audacious part of Wash’s death isn’t the permanent loss of by far the best character, it’s that you’re laughing when it happens. If the surprise death in LA Confidential is jarringly sudden, it pales in comparison to this. Wash dies mid-gag – a good gag at that – and immediately after doing something brilliant. It’s cruel, but it’s not callous or cynical writing – it’s an acknowledgement that main characters don’t automatically get fifteen seconds of extra life after fatal incidents, that they don’t always go out sacrificing themselves, that the timing isn’t predictable. Violent death is quick and horrible.

There’s barely a minute’s grace before the jokes start again. It ought to feel incongruous, but then the humour was never flippant to begin with – most of the jokes revolve around the fact that they’re all going to die almost immediately. It was always a diversionary device for the characters with the funniest lines, so it’s never more appropriate than in the wake of a tragedy. As ever, it’s Wash’s inherent reasonableness and Jayne’s nihilistically pragmatic approach to machoism that compete for the most laughs, and you have to wonder again why no other sci-fi is anything like this funny.

The tension – the fist-biting bit of my emotional cocktail – is partly down to the stepping up of the scale of the story. Firefly was always about a bunch of fugitives trying to stay off the radar and make money; Serenity is the first time their story has spilled over into something affecting the whole universe. The personal scale of Firefly’s plots was part of its charm, but Serenity proves that a plot which connects that to the truly epic can be even more seductive. And the perfect link between the two has been very carefully set up throughout the series: River. It always made it clear that she was significant in some way, finally discovering this significance – and its magnitude – brings Serenity’s universe into focus.

The Alliance isn’t cosmetically unlike Star Wars’ Empire, but the context is crucial – in Serenity, the Rebellion’s already been quashed. There’s no war, if you don’t like them you just have to stay the hell away from anything resembling quality of life. And though the Alliance is the bad guy, it’s not the only one, and in the intro to Serenity you actually get their perspective (and it’s not that much less reasonable than the outlook of a patriotic country today). When the crew’s ploy forces the Alliance to face their figurative demons literally, both Mal and his nemesis lament the loss of innocent life – an unpleasantness other sci-fi feebly avoids with clones, drones and aliens.

That nemesis is another application of the fierce intelligence with which Serenity hacks away at sci-fi convention. An empire is led by bureaucrats, not a samurai and an electric pensioner. The guy you send to capture a sensitive target is your best black ops man – neither a freelancer nor a government official. Someone who is actually employed to do this sort of thing, and ruthlessly, spectacularly efficient at it. He’s stylish, certainly – the killing of the scientist in his first scene is one of the most macabre screen assassinations in memory – but it’s an elegant application of necessary force rather than a superfluous flourish. And when it comes to killing everyone the targets have ever known, that luxury is dropped without hesitation. Like every good agent, his violence is committed in a passionate belief in the cause, and the same understanding of the necessity of secrets, under-handedness and technically illegal operations that a real spy needs. This guy reassures his victims that they’ve lead a virtuous life before he executes them. He’s not evil, not even cruel, just ruthless.

It’s also brilliantly refreshing to see an a bad guy who, when the girl sneaks up behind him during the hero-nemesis fight, turns round and kicks her really hard. Nemeses are sick of getting knocked out with vases! If you keep doing that shit, women of action films, they’re going to have to hit you quite hard!

It’s not just rare for sci-fi to be this intelligent, it’s rare for something this intelligent to be so emotional. Memento and LA Confidential, though unquestionably cleverer than Serenity and utterly gripping, never put my engagement with the excellent characters to use in making me feel things. Or at least, what they made me feel now seems vague and academic compared to the wonderful trauma of watching Serenity. It has brains, heart, and space zombies.