‘You’re talking about the end of every life on Earth! You’re half-human, haven’t you got any goddamn feelings about that?,” says James T Kirk to Spock, in Star Trek IV: The Voyage Home. A seemingly unstoppable natural disaster looks set to consume the planet, and the only chance of salvation is the ultimate long shot. No, not convincing American teenagers to stop going to the beach during a pandemic, but travelling back in time to fetch a pair of humpback whales in the hopes that they will tell an environmentally destructive interstellar probe to buzz off. It may sound absurd, but Star Trek IV: The Voyage Home teases the story out so it all clicks into place. It’s a film beloved by hardcore fans and mainstream audiences who otherwise thumbed their nose at the oft-stigmatised franchise.

When I saw it at age 12, I was only vaguely aware of Star Trek. I knew that Captain Kirk was a tough guy, Spock was logical and Leonard “Bones” McCoy was goofy. I also knew that some losers were so into this stuff that they could have conversations in Klingon. But about 10 minutes into this adventure (which is the conclusion to an arc that begins with Star Trek II: The Wrath of Khan and continues with Star Trek III: The Search for Spock) I knew I had no choice but to become one of the devoted – and frequently mocked – Trekkies. Like a Klingon Bird-of-Prey on a slingshot warp around the sun’s gravitational pull, my life had been sent on a new trajectory.

Fateful first viewing ... Star Trek IV: The Voyage Home. Photograph: AF archive/Alamy Stock Photo

The movie is brilliant in its simplicity. The Star Trek gang, normally zooming through space battles against aliens from weird realms in defence of their utopian, quasi-Marxist United Federation of Planets, is forced to come to us. By which I mean mid-1980s San Francisco. Yes, they can regularly outwit Romulans, but what about aggressive punks on public transport?

For the crew to achieve their goal they must split up. Sulu has to somehow acquire a helicopter. Chekov and Uhura need to collect energy leakage from a nuclear reactor. Scotty and Bones are tasked with building a tank out of transparent aluminium, a substance that hasn’t been invented yet. And Kirk and Spock must find the whales. It’s a tall order, and there are obstacles (such as Chekov getting captured by the US Navy) but they never stop thinking and never take their eye off the goal. And in a great modern spin, Kirk doesn’t get the girl.

That screening was like one you only see in movies with explosions of laughter and cheers. I raced home and rearranged my life to catch as many Star Trek reruns as possible, and a year later I hitched a ride on the USS Enterprise for the debut of Star Trek: The Next Generation.

So does the film that started it all still cast a spell? I can say, enthusiastically, yes. I know because I watched it recently while on my fourth consecutive Star Trek cruise.

When I said this fateful first viewing redirected my life, I meant it. I’ve been tangentially associated with the official Star Trek brand for close to a decade now, hosting events at conventions.

For a satisfying and clever genre film, Star Trek IV is every bit the equal to Back to the Future. You really don’t need to know anything about wider Trek lore to enjoy it.

Not everything I loved at 12 still resonates with me. (Do not go back and play those old Def Leppard albums.) But Star Trek IV: The Voyage Home is a time-travel trip I’ll always be happy to make.