Spock has used the Guardian to return to Earth in the 1980s, apparently to warn Earth about the ozone hole. However, as he is addressing an audience, Q turns up accusing him of breaking the Prime Directive by giving the warning and pointing out that it is a waste of time because Earth will be hit by an asteroid in a few hours. Spock thanks Q for delivering the real message and tries to get Q’s assistance in diverting the asteroid. Q claims he has been tricked and says he can’t be bothered to help, but Spock plays on Q’s vanity when challenging him to a contest of riddles. Q agrees and then loses the contest and finally agrees to divert the asteroid, but only changing its orbit so it won’t hit until 2025. Then Spock and Q go to get something to eat.
After the meal they are back addressing the audience, when suddenly Spock and Q find themselves on the asteroid heading for Earth, and both of them are behaving strangely. Spock has taken on Q’s flippant attitude and Q has become analytical, but neither now seem to have the power to divert the asteroid or get themselves off it. Q tries calling 777 (the Continuum’s emergency number) but he isn’t recognized as a Q while Spock is, but Spock then allows Betty (the person in the Q Continuum who responded to the call) to hang up so she could answer another call. When the phone rings again, it is Petunia from P (some form of universal police force that comes before Q), who accused the two of them of Violation 165 (violation of the temporal sequence), but she does apparently allow the asteroid to be diverted and returns the two of them to the conference hall as themselves.
The Excelsior is sent to Stentor (which had had brief contact with Starfleet 20 years previous) because transmissions from the planet were interfering with subspace transmissions. Arriving at the planet they find a huge transmission tower that was mainly transmitting snippets of radio signals from Earth (which are claimed to be 'messages from the gods') and there are also messages from Citizen Gazi against Kondravex (who is leader of the planet). Sulu meets with Kondravex and tries to get her to join in discussions with Gazi. She says that as a Sensorial she cannot meet with a citizen. The transmissions are being magnified by the Flute Trees that Kondravex claims used to talk to her with the voices of the dead, but now the trees are being damaged, and she feels her life is coming to an end. Sulu comes to realize that Gazi is waging a sort-of religious campaign and decides to give him a conversion experience. Science Officer Terence Spiro beams down masquerading as one of Gazi 's followers and short-circuits the broadcasting tower and locates Gazi and has him beamed to the Excelsior. When he learns who are really behind the supposed 'messages from the gods', Gazi (who was born into a Sensorial family and was really trying to unite the planet in a misguided way) agrees to talks with Kondravex, and she finally goes along with it. The Excelsior leaves the planet, hoping that their future will be brighter, and Sulu gets cleared of breaking the Prime Directive in regard to his actions. [Timeline: circa Stardate 8764.3]
Sulu is aboard the one-man shuttle, Nelson, heading for a diplomatic mission on Clarion 7. However, he diverts his flight to Sigma Cameron 4 (believed to have been related to the lost Shalaki Empire) when he hears that archaeologist Constance Allenwood is heading there. Sulu had been on an expedition there 20 years previous, and his Chief Science Officer, Commander Flynn Connor, had ended up basically comatose. Sulu had recently made one his regular trips to see Connor, and since then had had a couple of troublesome dreams about the expedition where Connor seemed to be trying to pass on some information. Sulu sends a warning to Allenwood, but she ignores it. When Sulu arrives, he finds Allenwood lying on the sand with her hands on a red orb, an orb that Connor had been getting Sulu to hold in his dreams. Sulu tries to remove the orb from Allenwood's hands, but a tall golden-skinned person appears, calling himself Councilor Zhan of the Shalaki, and the surroundings change to a forest. Zhan tries to take over Sulu's body and eject his soul/consciousness/katra, but Sulu puts up resistance and Zhan challenges Sulu to a dual. That doesn't go well for Sulu until he recalls from one of Connor's logs that Zhan creates imaginary environments, and then Sulu is able to kill Zhan. The consciousnesses of Connor and Allenwood return to their respective bodies, and Allenwood now takes Sulu's advice to abandon her expedition, and instead she goes to compare notes with Connor who is now fully recovered. [Timeline: circa Stardate 11611.8]
Sulu is sent to be witness at a peace ceremony between the Denkai and the Krikiki, but he is horrified when the leader of the Krikiki breaks his own son's (Prince Rukrell) legs and plans to hand him over to the Denkai as a token of his peaceful intention. Worse still, he learns that the Denkai would be cutting the boy's vocal cords because the Krikiki 's voice is abhorrent to them. Sulu wants to get out of his envoy roll, but then Starbase 3 is taken over by warriors, known as Caftek Denkai, who capture and plan to kill the prince in order to stop the peace. Sulu attempts to rescue the prince, but the prince appeared to actually want to turn himself over to the Denkai. Sulu does manage to set off a high-pitched noise that disables everyone on the station. The Denkai and Krikiki delegations arrive at the station while everyone is still unconscious, and they subdue the Caftek warriors. Sulu had realized that the prince was willing to give himself up to stop the deaths of millions in the war, and Sulu is finally honored to play his part in the ceremony. And the Denkai, seeing that the prince had been willing to keep quiet, they forego the slitting of his vocal cords, and Sulu hopes that as peace is consolidated the prince will be allowed to return to his people.