The crew now learns that Chekov is injured and has been taken to a hospital for surgery, not expected to live. At this point there is a payoff to the paradox that has been spread out between two distant points during this film. Spock has twice noted that humans are not logical, first to his mother before he left Vulcan, who reminds him that his "flawed human friends" risked their lives and careers to rescue him, in spite of the axiom that the needs of the many outweigh the needs of the one. The second time he addresses Gillian, just after she showed the whaling video to the tour group. "To hunt a species to extinction is not logical," Spock observes. "Whoever said the human race is logical," Gillian says.

This is the human paradox. Not being "logical" means noble sacrifice, but also destructive lack of forethought. The solution to the paradox is consciousness. You make the choice. Spock counsels that they must rescue Chekov. Is that logical? Kirk asks. No, Spock says, but it is the human thing to do.

But in this movie the actual rescue turns into a Marx Brothers scene in the hospital, with McCoy (playing Groucho this time) in his element again, aghast at what we flatter ourselves is Modern Medicine ("it's the goddamn Spanish inquisition"). He also has a nice face-off with an equally irascible 1980s surgeon, each of them convinced the other is a quack. A certain professional arrogance seems timeless. One of the best-remembered bit-part lines in this film was a last minute addition not in the script. The escaping heroes pass the elderly woman to whom McCoy has given a pill in lieu of dialysis. "Doctor gave me a pill and I grew a new kidney!" she shouts exultantly, over and over. Talk about fast relief.

They all return to the Bird of Prey, and Kirk says goodbye to Gillian. In Nick Meyer's script, it really is goodbye: Gillian decides to stay, in order to work towards preventing the whales' extinction. It does make the point more strongly about, as Meyer said, "...the importance of people in the present taking responsibility for the ecology, and preventing problems of the future by doing something about them today..."

But the filmmakers chose the Eddie Murphy script path, as Gillian jumps into Kirk's arms (somehow figuring out that two could be transported safely as one, which probably would have given Geordi LaForge a fit) and goes along. Her reasoning is defensible: that the 23rd century would now need a biologist who knows something about whales. However, her sudden unexplained absence from the 1980s is fodder for a Trek novel (Do her coworkers reasonably assume she committed suicide in her despair over the whales? She becomes a environmental martyr, Greenpeace names their boat the Gillian Taylor and...what happened to those two whales anyway?) As for what it does to the timeline...let's not go there.

Kirk returns to the bridge, and in an exchange that happens so fast it’s easy to miss, we hear Spock for the first time swear appropriately. “Spock, where the hell’s that power you promised me?” Kirk demands. “One damn minute, Admiral,” Spock replies. Shatner does a brief take, as Scotty’s voice is heard, anxious to “go get George and Gracie.”

Now our intrepid crew must get to the whales before the whalers do. The Oscar-nominated score by Leonard Rosenman (the second for Trek, after Jerry Goldsmith's for Trek I) is particularly effective in several scenes, and the whale trawler sequence is one of them. The harpoon clunking off the side of the Klingon Bird of Prey menacing above the whaler is the ecologist's equivalent of Spock neck-pinching the boom box punk. It's satisfying wish fulfillment. Both scenes merit cheers, though this one is particularly deserving.

George and Gracie are saved, then beamed aboard, prompting one of James Doohan's most luminous movie moments: "Admiral!" Scotty cries, his voice echoing with the centuries. "There be whales here!"

It's worth pointing out, as the action accelerates, that not only is the storytelling tight in a way that it seems more recent movies often can't manage, but the pace is more measured, with slower moments preparing for the fast-paced action. This is also part of effective storytelling.

So here, between the big action moments of playing Greenpeace with a Bird of Prey to rescue the whales and beam them aboard, and before the attempt at reverse time travel, there are several slower scenes that develop character story and theme, as well as building towards the action payoff.

We see two moments of the other half of the McCoy-Spock relationship, the affection and admiration. McCoy senses that Spock is vulnerable and uncertain as the crew and the future depend on his calculations and other efforts to get them back to the correct moment in their 23rd century. He tells Spock that it's all right to "take his best shot" even if he isn't completely certain. Spock replies that guessing isn’t in his nature. “Nobody’s perfect,” McCoy replies, with a twinkle, and why not? He’s saying that the Vulcan isn’t perfect because he can’t guess---that is, he can’t accept the imperfection of uncertainty. Being imperfect is essential to being human, and the ability to guess is a strength, not a weakness.

Spock accepts this, and when Kirk asks him about certain variables (which actually he should know, but that's not the point) he admits that he is guessing. Even if we don't know that Spock's arch dismissal of guessing was a running gag in the series, Kirk's reaction of apparent pleasure works well---it is a moment of warmth. This Spock, however, is still more innocent than prickly. He thinks Kirk didn't understand. Once again, McCoy gives him reassurance rather than criticism: Kirk trusts his guesses more than he would trust other people's facts. Spock's head comes up, his chin off the floor now. Is this a compliment? McCoy affirms that it is. Now Spock is filled with the confidence of his captain, which gives him confidence without arrogance. He says with great dignity and humility, "Then I will try to make the best guess I can." What a lovely moment.

Then Kirk and Gillian have a moment watching the whales in their tank. Kirk recalls the D.H. Lawrence lines, which work quite well here, and he muses naturally on what amounts to the film's message: "It's ironic---when man was killing these creatures, he was destroying his own future."

Immediately an exchange between Kirk and Scotty in Gillian's presence alerts us to the jeopardy that still remains---the chances of getting back are slim. "A miracle?" Scotty says. "That's yet to come."

It's good storytelling and it's a provocative idea, for ordinary risk assessment would suggest that none of this should have been attempted if the chances of the last step, getting back, were so grim. But at this point everyone is happy, because they have done what they set out to do, and they are together. They will accept whatever comes next.