TREKCORE > DS9 > EPISODES > THE ADVERSARY > Synopsis

Episode Synopsis by Tracy Hemenover

Sisko records his last log as commander of Deep Space Nine. The reason: he's being promoted to Captain. At the ceremony, Jake proudly pins the fourth pip onto his father's collar, and everyone applauds. Present, along with the station's senior officers, Jake, Quark, and Eddington, is Ambassador Krajensky, a Federation official. After a general round of congratulations, O'Brien lifts a glass in salute. "Here's to the newest and best captain in Starfleet. And all I can say is, it's about time."

Krajensky takes Sisko aside for a private conference, saying intelligence reports indicate there's been a coup on the Tzenkethi homeworld. Starfleet wants to remind the Tzenkethi that the Federation is committed to protecting their colonies near the border, and to that end, Sisko is to take the Defiant out to "show the flag" on a week-long patrol. Krajensky will come along as an observer.

In the Defiant's engine room, Sisko orders O'Brien to do a complete overhaul of the deflector shield generators and targeting sensors, and leaves the Chief to his work. As O'Brien starts in, he thinks he hears something behind him, but when he looks, there's nothing. "Getting jumpy in your old age, O'Brien," he murmurs to himself.

As they walk to the Defiant, Sisko chats to Dax about Kasidy, who is currently off on a cargo run and doesn't know yet about the promotion. Dax unabashedly fishes for information, and Sisko finally lets on that he plans to take Kasidy to the 1964 World Series. "You do like her," Dax exclaims, pleased. They enter the Defiant's bridge, where all the officers, including Odo, are at their stations, with Krajensky looking on. Sisko orders a course laid in to the Tzenkethi border. "Aye, aye, Captain," Dax responds happily.

O'Brien is working in a Jeffries tube when he hears noises and goes to investigate. He runs into Bashir, of all people. The doctor nonchalantly says he was just connecting his new diagnostic console to the medical bay's power grid. "Just putting my engineering extension courses to work. Besides, I know you have your hands full." He crawls away, and O'Brien checks his handiwork. "Not bad for an extension course," he admits to himself.

Sisko has a talk with Eddington, who assures him that if hostilities occur, he will escort the ambassador off the bridge. Eddington adds that he agrees with O'Brien that it was about time Sisko was promoted. Sisko appreciates the sentiment, but says it doesn't really change anything. "People don't enter Starfleet to become commanders, or admirals for that matter," Eddington points out. "It's the captain's chair that everyone has their eye on. That's what I wanted when I joined up. You don't get to be a captain wearing a gold uniform." Sisko suggests that he could always switch to command, but Eddington asks who would protect the ambassador?

Twelve hours from the border, the Defiant receives a distress signal from Barisa Prime. It says they're under heavy fire from Tzenkethi warships. The Defiant then loses contact. Sisko has Dax set a course there, and send a message to the closest starship, but Odo, ordered to notify Starfleet Command, says he's having trouble getting through due to a power fluctuation in the communications system. Dax can't send her message either.

O'Brien and Dax go to check out the transceiver assembly. Inside a panel near where O'Brien encountered Bashir earlier, they find a strange sort of device attached to the systems inside. It seems to grow and move as they look at it, spreading like a parasite. O'Brien can't remove it because there's a forcefield. They go to check the other command systems.

There are more of these things in Engineering; they've attached themselves to almost every critical system, O'Brien tells Sisko. He's still working on how to get past the forcefields. "I guess the question is, how did they get aboard?" asks Sisko. "Or should I say, who placed them here?" O'Brien says it definitely happened after they left the station; the things weren't present when he did a systems check before their departure. "Which means someone aboard this ship is a saboteur," Sisko says grimly. It could be any of the 47 people on board. O'Brien reluctantly mentions having seen Bashir in the Jeffries tube, connecting a medical console into the power grid, which is next to the communications relay. "Are you accusing Julian of sabotage?" Dax asks. "No one's accusing anyone of anything," Sisko says. "But I want to talk to Julian." However, Dax says she's got a better idea.

Sisko gathers several people together on the bridge and tells them someone on the ship is guilty of sabotage. Dax says that one of the devices was found in the warp plasma conduit, meaning that whoever planted it there would have been exposed to trace amounts of tetryon particles, which will still be detectable on the saboteur. Therefore everyone will be scanned for the particles, starting with them. Dax says she and O'Brien have already scanned positive, since they had opened up the warp core controls. Of course, if no one else tests positive, they'll be the prime suspects. Dax proceeds to scan Sisko (clean), then Kira (clean); then she comes to Bashir. He too reads clean.

O'Brien remarks that he's relieved, since Bashir was in that conduit the other day. Bashir is puzzled; he hasn't been in the conduit. At the same time, Dax is scanning Krajensky, and realizes that it's him. Suddenly Krajensky morphs, knocking people aside and disappears up an access hatch into a conduit. "It's a Changeling!" exclaims Kira. Odo looks disturbed.

Almost immediately, the cloaking device goes into operation, and Sisko orders Eddington and Odo to find the Changeling. He also orders Dax to come to full stop, but the helm doesn't respond; and O'Brien can't disengage the cloaking device. Kira reports that the weapons array has activated. "The ship's no longer under our control," Dax says.

A bit later, Odo and Eddington haven't been able to find the Changeling, and Eddington supposes it's possible he could have been transported off. "He's still here," Odo says. "He won't leave until he's completed his mission." Sisko's guess is that the Dominion hopes to start a war between the Federation and the Tzenkethi. The transmission from Barisa Prime could have been faked, using the device found in the communications array. The entire mission, in fact, could have been engineered by the Dominion -- the biggest clue is that no one has seen a trace of the real Krajensky or his remains, meaning that he was probably replaced before they left the station; possibly before he ever came to DS9. So everything Krajensky told them could have been a lie. "And now here we are, cloaked, armed for battle, and heading into Tzenkethi space," says Sisko. "If we can't stop this ship before we cross the border, we may wind up causing a war rather than preventing one." The reason for this ploy on the part of the Dominion is obvious, to destabilize the Alpha Quadrant and make it easier for them to move in.

Eddington comments that he wishes the internal sensors were online; they would make it easier to track the Changeling. "I'm not sure the sensors would help," says Odo. "If you scan me when I'm a rock, you'll detect a rock. I may not be able to duplicate a humanoid perfectly, but I'm guessing he can." Bashir notes that Krajensky had registered as human when he was scanned for tetryon particles. "Then right now the Changeling could be anything or anyone on this ship," Kira notes with dread. To narrow their enemy's options, Sisko has Odo confine all nonessential personnel to quarters and seal them in with forcefields. No one will be left alone. They have seven hours before they reach Tzenkethi space.

Bashir goes into the medical bay with a security officer as Odo and Eddington pass out phasers. Eddington offers one to Odo as well, but Odo declines. "I don't use them. Besides, in the history of my people, no Changeling has ever harmed another. I'd hate to be the first." "Apparently that Changeling doesn't feel the same way," Eddington points out. "If we don't stop him, no one on board will escape unharmed. Including you." Odo concedes that. "You may be right. But I've been a security officer most of my humanoid existence. And in all that time, I've never found it necessary to fire a weapon or take a life. I don't intend to start now." Just then they are called to the engine room by O'Brien.

Dax is unconscious on the floor; O'Brien had gone to get a tool, and found her this way when he got back. Bashir (who is not with the same security guard as before) says she has a severe concussion and hustles her off to sickbay. Later he updates Sisko and Kira; Dax should be all right in a day or two. It appears O'Brien is going to have to regain control of the ship without her. "Taking Dax out makes O'Brien's job a lot harder," Kira remarks worriedly. Sisko looks determined. "One thing's for sure, we're not going to start a war with the Tzenkethi. If O'Brien can't regain control before we cross the border, I'll have no choice but to destroy the Defiant."

Everyone is divided into two-person teams, armed with phaser rifles reconfigured to fire an energy pulse which will avoid damaging equipment but will affect the Changeling. They will systematically sweep every inch of the ship. "What if the Changeling's not out there?" a Bolian security officer asks nervously. "What if he's one of us?" "That's why everyone will be in teams," Sisko says. "Keep your partner in sight at all times." And if they see anyone without a partner, they are to be escorted to the brig, so as not to take any chances.

Kira is paired off with the rather paranoid Bolian, and Odo with Eddington. "What would you be if you were him?" Eddington asks as they check out a Jeffries tube. Odo says, "I wouldn't know. I'm not him." "He is one of your people," Eddington says. "Can't you put yourself in his position, try to anticipate his next move?" "I've thought about it," Odo admits. "But the truth is, I don't understand my people all that well."

Sisko checks out another area with his partner, another security officer. Suddenly a part of the bulkhead morphs, breaking the security officer's neck, and escapes. Sisko, whose hand is cut, sends out an alarm and takes off in pursuit. Then he comes across the Bolian, who had gotten separated briefly from Kira, and now is certain she's the Changeling. For her part, Kira thinks maybe it's the Bolian. Sisko orders them to put down their weapons, but the Bolian refuses, and is about to shoot Kira when Odo arrives and decks him. Eddington then comes on the scene as well -- he and Odo have also been separated.

"Then we've got a problem," Sisko says to Odo. "Any of us could be the Changeling. You, Kira, Eddington -- even me." "Not you," Odo says suddenly, looking down near Sisko's feet, where several drops of blood have landed from his cut hand. "When blood leaves a humanoid body, it's still blood. But when any part of me separates from my body -- " "It reverts back to a gelatinous state," Kira finishes. Sisko orders Bashir to meet them in the mess hall.

Bashir draws blood from everyone involved. First the Bolian, who is really a Bolian. Then Kira, who is really Kira. "Try not to look so surprised," she tells the Bolian. Eddington volunteers to be next, and Bashir does him too. This time, the blood morphs into Changeling goo. Rifles are leveled at Eddington, who looks stunned.

They all escort Eddington down a corridor, protesting all the way. He is about to be put into a room when suddenly a forcefield on a nearby door shorts out. There stands another Bashir. "Would someone please get me out of here?" There is a moment of frozen surprise as the two Bashirs look at each other and everyone looks at them, then the one in the hall quickly morphs and shoots into a vent in the ceiling. Odo morphs too and goes in after him. A call comes from the bridge at that moment, saying they're entering Tzenkethi space.

There are no signs of Tzenkethi ships, fortunately, but now the Defiant has changed course, headed for M'Kemas III, a Tzenkethi settlement. There are twelve minutes until they are in weapons range. Sisko has no choice but to initiate the auto-destruct sequence, and Kira adds her authorization as well. The countdown is set for ten minutes. Sisko then calls O'Brien in the engine room. "I could use some good news right now, Chief." O'Brien says he may be able to shut down all the forcefields. He will have to do it in less than seven minutes. The real Bashir enters the bridge to let them know that he's filtered out most of the sedatives the Changeling gave Dax.

O'Brien is working with another engineer, telling him that when they set off their device they may lose the protective field around the warp core. Then a Changeling morphs in from a vent and becomes Odo in humanoid guise, having lost the Changeling in the conduits. Almost simultaneously, another mass of goo enters through another vent, and also morphs into Odo's humanoid form. Both Odos commence trying to convince O'Brien that they're the real thing. Finally O'Brien decides he doesn't have time for this. "I've more important things to do than play Choose the Changeling." He has his subordinate keep a phaser on both of them.

The minutes tick down until finally the second Odo asks what O'Brien is doing. "You'll see," says the Chief. He finishes work on his device, and it is activated, shorting out all the forcefields, including the one around the warp core. As O'Brien tells the other engineer to shut down the main power grid, finally the second Odo morphs into a recognizably different Changeling and attacks; both O'Brien and the engineer are knocked out, and the engine room is sealed.

The real Odo pulls the Changeling off O'Brien, but then the Changeling punches Odo in the midsection, forcing a Link. "Why are you protecting these solids? You don't belong with them. You belong with us." Odo can't speak, his body racked with pain as solidity ebbs away. "Let go," the Changeling urges. "Don't you see? You've lost. It's too late for you to help them, but it's not too late to help yourself. Link with me, Odo. We can escape together." Only Odo's head is solid by now. But then he rallies, solidifying back into his humanoid form. "I...don't...think...so," he grates, and now it's his turn to force the Link. The other Changeling goes completely gelatinous, and Odo ends up pushing him against the unshielded warp core. An energy discharge hurls Odo away.

Odo hurries to O'Brien and helps him up. As O'Brien gets back to work, with auto-destruct in two minutes, Odo turns back to his fellow Changeling, whose upper body is in a ravaged humanoid form. "I never wanted to harm you," Odo tells him. The Changeling nods, as if he understands, and pulls Odo closer to whisper a message. Odo watches in anguish as the Changeling dies, collapsing into a pile of black powder.

O'Brien calls the bridge with the news that he's restored control to the helm. Sisko instantly orders a course change, and aborts the auto-destruct, with Kira's aid. The phaser banks power down; they can now go home.

After they return to DS9, Sisko is concerned about Odo, who hasn't said a word since they left Tzenkethi space. The real Krajensky was supposed to be on his way to Risa for a vacation, but never arrived; he's believed to have been kidnapped or killed. As for the coup on the Tzenkethi homeworld, it never happened. Odo then enters in the middle of the meeting, his manner hesitant.

"Captain, there's something you need to know," he tells Sisko. "The Changeling -- before he died, he whispered something to me." Odo pauses, struggling with an inner conflict. "He said, 'You're too late. We're everywhere.'"