Forty years ago, the Star Trek movie franchise reached its Solaris stage with this mystic and melodramatic threequel, written and produced by TV veteran Harve Bennett and directed by Leonard Nimoy himself. The Search for Spock (and how that title must have startled everyone still getting over the shock of his demise) dealt with the mysteries of matter, organisms, death and eternal life. The last two of these were especially piquant considering that the audiences at the time had to deal with something that is forgotten now: the unease and even shock at seeing the characters’ faces, so youthful in the concurrently running TV show, looking suddenly older, blown up to big-screen size.

This is a film about the passionate bromance between Kirk and Spock – and above all about sacrifice. In the previous film, of course, Spock had died, thus teaching future franchise creators a lesson about how a death can electrify the fanbase. This one begins by remembering his poignant farewell to Kirk in a small black-and-white panel in the centre of the screen; rather a coup de cinema. And yes, it is a genuinely sad moment, accurately depicted in the famous episode of Seinfeld when George Constanza realises that he is more devastated by Spock’s death than by that of his own wife.

But as the USS Enterprise comes home damaged, under the command of Kirk (played of course by the boyish William Shatner), after the fateful battle with Khan in which Spock had met his end, Dr McCoy (DeForest Kelley) starts behaving strangely, because Spock’s spirit has entered his body. On the distant planet Genesis, created by the Genesis device (which the Klingons wish to own, convinced of its potential as a weapon) Spock’s body has been reincarnated in the form of a child, ageing rapidly as the planet itself begins to hyper-evolve towards its own destruction. Kirk and his crew effectively steal the Enterprise (which had been officially decommissioned) and piratically head out to Genesis where this young neo-Spock faces a desperate situation at the hands of the Klingons, along with two others: Kirk’s son David (Merritt Butrick) and the Vulcan Saavik (Robin Curtis).

You will have to disregard the fact that Kirk and a handful of intimates manage to pilot the Enterprise on their own (that giant ship which otherwise seems to need a whole city-state of uniformed crew). But this episode is written and performed with muscular vigour and attack, and there are some nice moments, such as Dr McCoy’s louche appearance at a bar where people can play next-level video games – including a kind of VR hologram mini-table tennis, a very exciting looking device which we still don’t have in 2024.

How extraordinary to see what Kirk is prepared to sacrifice for Spock: the Enterprise and even loved ones closer than that. You can even forgive the franchise for cheating the issue of Spock’s death, though another death seems forgotten relatively quickly. The original cast members bring a certain gravitas.

• Star Trek III: The Search for Spock is in UK cinemas from 14 June.

• This article was amended on 14 June 2024 to correct a reference to Vulcans wanting to own the Genesis device; it should be Klingons.