Jj Abrams’s new Trek instalment is as glitzy as his first, but it’s the arrival of Benedict Cumberbatch as a mysterious new foe that fuels this outing for the Enterprise.

The initial bromance excitement of the great Kirk-Spock adventure now being over, the second episode brings us to the anticlimactic man-marriage of their rebooted career aboard the USS Enterprise. It’s the latest in what promises to be a long series of films: a big, glitzy, high-energy drink of a movie with a glossy tech sheen, long on lens flare, shorter on other kinds of flair, and only showing real excellence in the continuing subtle, seriocomic performance of Zachary Quinto as Spock.

The new Star Trek franchise is watchable, but already showing signs of getting tangled up in all the growing strands of self-created mythology and perhaps more worryingly still, it looks as if director JJ Abrams and screenwriters Roberto Orci, Alex Kurtzman and Damon Lindelof have not quite grasped what was so great about the first movie in 2009: the all-important dynamic between the captain and first officer.

Right off the bat, Star Trek Into Darkness zaps us with the darkest fear of all: the death of Spock, that potent Trek subject that I can’t help associating with the episode of Seinfeld in which George reveals he is actually more moved by Spock’s demise than by the death of his own fiancee. The crew are all assembled: Chris Pine is Kirk, and Uhura (Zoe Saldana) is still in a relationship with Spock, though the affair is naturally subordinate to his male bond with the captain; Sulu (John Cho) is there; Simon Pegg plays Scotty with a terrible Scottish accent that is still weirdly better than Chekhov’s Russian accent, despite the fact that Anton Yelchin, playing him, was actually born in Russia. Karl Urban plays grumpy medic Bones, who cordially dislikes Spock. (In times of old, we wondered about a deliberate obscenity in “Are you out of your Vulcan mind?” In this movie, Bones tells Spock: “Boy, you really are a comfort.”) And Kirk gets some love interest with a new scientific officer, Dr Carol Marcus (Alice Eve), who just so happens to appear fleetingly in her underwear.

They begin on an observation mission, investigating a primitive tribe on a jungly planet, but a desperate situation develops from which Spock cannot be rescued without infringing those Starfleet rules for which he is such a stickler. Spock is apparently ready to die. The incident creates tension between him and the captain that colours their entire working relationship as they tackle a new terrifying enemy, the mysterious John Harrison, played by classy British actor Benedict Cumberbatch. This sinister figure causes a massive explosion in London, and then escapes to enemy territory, apparently intent on causing a catastrophic war.

As the supervillain, in closeup, Cumberbatch really does give it the full Blue Steel. It’s more like Indigo Steel, or Topaz Steel. As he faces off with Kirk, he does a lot of impassive and charismatic gazing, indicative of infinitesimally amused unconcern.

But I like my Brit baddies to have droll dialogue (like Loki in The Avengers), and John Harrison has none; he does all this supercool gazing, even when he is getting punched repeatedly in the face, but he is the tiniest bit dull. And anyway, Kirk already has a hugely evolved, scarily cerebral sparring partner – Spock! We are heavily invested in Spock and his fascinatingly tense, prickly, and sometimes antagonistic relationship with Kirk. There are now three people in this emotional guy-namic. John Harrison is a bit of a third wheel.

A bouquet has to be thrown to Simon Pegg, whose comic timing and energy – and self-evident love for what he’s doing – is turning Scotty into a powerhouse character. But above all, Quinto is enduringly great: his Spock is vulnerable, sensitive, emotionally constricted, but idealistic and heroic as well. The franchise will always have life with him on board.