Commander's log, stardate 48959.1.
lt is with mixed emotions that l record my final Commander's log.
The last three years have been my most demanding and rewarding.
l only hope that the future will hold even greater challenges.
There's something l've wanted to say to you for a long time.
Now that l have the chance, l'm going to make it short and simple.
Congratulations, Captain Sisko.
Does another pip on your collar mean l can't disagree with you any more?
- lt just means l'm never wrong. - We'll see about that.
Curzon would have been proud of you, but not as proud as l am.
That means a lot to me, Dax.
Though l don't fully understand this obsession with rank and title,
if anyone deserves to be promoted, it's you.
Thank you, Constable.
As someone who is obsessed with rank, congratulations, Captain.
That goes for me too, Captain.
- This calls for a toast. - Better not be from a replicator.
Chateau Cleon, 2303. l already put it on your account.
- Can l? - l guess a sip won't hurt.
Well...
Here's to the newest and best captain in Starfleet.
All l can say is, it's about time.
- Here, here. - Cheers.
That's enough.
Thanks for coming, Ambassador.
Those pips look good on you, Captain.
To be honest, l'm not really here for the ceremony.
l had that feeling. What can l do for you?
Our reports indicate there's been a coup d'état
on the Tzenkethi homeworld.
l doubt anyone will miss the Autarch.
l know l won't.
lt's too early to tell who's in control,
but we don't want to take chances.
We need to remind the Tzenkethi that the Federation is committed
to protecting our colonies.
- You want to show the flag. - Exactly.
The Defiant will leave in two days on a week-long patrol.
l'll be coming along.
l'm looking forward to seeing the Defiant in operation.
You won't be disappointed. She's a fine ship.
With a fine crew. What do you say we get back to the party?
{y:i}For he's a jolly good fellow
{y:i}For he's a jolly good fellow
{y:i}Which nobody can deny
- Hip-hip! - Hooray!
l want a complete overhaul of the deflector shield generators.
Take on a full complement of photon torpedoes.
lf the Tzenkethi start any trouble, we'll be ready.
l don't doubt it, Chief.
Captain?
Getting jumpy in your old age, O'Brien.
My son thinks l should say something profound on this occasion.
He even offered to write me a statement.
l told him l'd take care of it,
but the only thing l can think of is:
Begin Captain's log, stardate 48960.9.
Have you told her yet?
Told who?
Captain Yates. About your promotion.
l barely had time to send my father a transmission.
l don't even know where Kasidy is.
She's hauling a load of duridium ore to Solais V.
You could contact her on subspace.
l'd rather tell her in person.
When's she due back?
- About a month. - A month!
There's nothing worse than a long-distance relationship.
l wouldn't call it a relationship, Dax.
l've only taken her out once.
OK, twice.
The exact figure is three times.
She's quite an interesting woman.
A little opinionated, but she has a nice sense of humour.
And?
What do you want me to tell you, Dax?
That you miss her, that you can't wait to see her.
l don't know. Anything.
Kira, O'Brien, Bashir. They're all dying of curiosity.
l have to tell them something.
Fine. You tell them when she gets back,
l'm going to take her to the holosuite
and we're going to watch the seventh game of the 1 964 World Series.
You do like her.
- Captain on the bridge. - Ambassador.
- All stations report. - Helm ready.
- Weapons ready. - Communications system standing by.
Engines on-line.
- Release docking clamps. - Docking clamps released.
- Engage thrusters. - Clearing the station.
Lay in a course for the Tzenkethi border.
- Aye, aye, Captain. - Engage.
Hello. Who's there?
Julian!
- You called me, Chief? - Why didn't you answer me?
- l had this spanner in my mouth. - What are you doing here?
Connecting my new diagnostic console to the medical bay's power grid.
Just putting my engineering extension courses to work.
You have your hands full.
- Oh. Where are you going now? - l'm done.
Not bad for an extension course.
You wanted to see me, sir?
Yes, Commander. lt's about Ambassador Krajensky.
Please.
l know Starfleet doesn't intend this to be a combat mission,
but l want to make sure the ambassador is kept out of harm's way.
lf hostilities occur, l'll see the ambassador is escorted off the bridge.
- He won't like it. - l won't let that bother me.
Very good, Commander. That'll be all.
Captain.
l just want to say that l agree with what Chief O'Brien said.
About your promotion. lt's about time.
l appreciate the sentiment, but it doesn't change anything.
l have the assignment l want, the crew l want.
The rank doesn't make much difference.
You'd be surprised.
People don't enter Starfleet to become commanders or admirals.
lt's the captain's chair that everyone has their eye on.
That's what l wanted,
but you don't get to be a captain wearing a gold uniform.
You could always transfer from Security to Command.
Then who would protect the ambassador?
Dismissed, Mr Eddington.
Thank you, sir.
Captain's log, stardate 48962.5.
We are 1 2 hours from the border.
l haven't been in this area since the last Federation-Tzenkethi war.
Being here brings back a lot of memories, most of them bad.
We're receiving a priority one distress signal from Barisa Prime.
Put it through.
...under heavy fire from Tzenkethi warships.
Can anyone hear me? This is...
- Constable? - We've lost contact.
Try to re-establish.
lt's no use, Captain. They're gone.
Captain's log, supplemental.
We've been unable to re-establish contact with Barisa Prime.
l've no choice but to assume we are at war with the Tzenkethi.
Set a course for Barisa Prime.
l want continual scans for Tzenkethi ships.
Constable, let Starfleet Command know what happened.
Major, what other starships are in this sector?
The closest is the Ulysses. They're in the Helaspont Nebula.
That puts them 20 hours away at maximum warp.
Transmit a message to Captain Entebe on the Ulysses.
l can't get through to Starfleet.
There seems to be a power fluctuation in the communications system.
The problem must be in the transceiver assembly.
l need that system back on-line.
- Lieutenant, l could use some help. - Major, take the helm.
What do you make of this? l've never seen anything like it.
lt's spreading through the system like a parasite.
lt's linked to key points within the transceiver.
We'd better get it out of there.
A force field.
- Come on. - Where are we going?
To check the other command systems. l have a bad feeling about this.
These things are all over the ship?
They've attached themselves to the communication relays,
the transporter, the deflector shield grid.
Almost every critical system.
ls there any way to get past the force fields?
We're still working on it.
l guess the question is, how did they get aboard?
Or should l say, who placed them here?
l don't know who did it, but it happened after we left the station.
l ran a check before our departure. They weren't there then.
Which means someone aboard this ship is a saboteur.
We've got 4 7 people on board.
Any of them could have planted those devices.
Chief?
lt's nothing, sir. Not even worth mentioning.
lt doesn't sound like you're too sure about that.
l saw someone crawling about in one of the Jefferies tubes the other day.
- Who? - lt was Julian.
He was connecting a medical console to the power grid.
Which is right next to the communications relay.
Are you accusing Julian of sabotage?
No one's accusing anyone of anything. But l want to talk to Julian.
Wait. l think l have a better idea.
This crew has been through a lot together.
l would trust any one of you with my life.
But after looking at the evidence, there's only one conclusion l can draw.
Someone on this ship is guilty of sabotage.
The Constable and l can begin questioning the crew.
That won't be necessary. Lieutenant.
We found one of the devices planted in the warp plasma conduit.
Whoever put it there
would have been exposed to tetryon particles.
Those particles would still be detectable on the saboteur?
Yes, but not for much longer. They dissipate quickly.
You're going to scan the crew for tetryon particles?
- Starting with the senior staff. - O'Brien and l scanned positive
since we opened the warp core controls.
You realise that if no one else tests positive...
We'll be the prime suspects. Yes, we know that.
We might as well get started.
- You're clean. - l'm glad to hear it.
Might as well do me next.
You're OK, too.
Julian.
Of course.
- Nothing. - You sound relieved.
l am. You were in that conduit the other day.
Ambassador, if you please.
- l wasn't in a conduit. - l saw you there.
lt's a changeling.
We've cloaked. Lieutenant, bring us out of warp.
Full stop, now. Deploy security teams immediately.
l want that changeling found before he can do any more damage.
The helm's not responding.
l can't deactivate the cloaking device.
The phaser banks are charging.
We've got photon torpedoes ready to launch.
The ship's no longer under our control.
Our security teams have gone over every centimetre of the ship,
questioned every crew member. We still haven't found the changeling.
Could he have been transported off the ship?
At warp? lt's unlikely.
But with Dominion technology, l suppose it's possible.
He's still here.
He won't leave until he's completed his mission.
lt looks like the Dominion is hoping to start a war
between the Federation and the Tzenkethi.
The Tzenkethi are doing a good job of that by themselves.
The transmission from Barisa Prime could have been faked
using the device we found in the communications relay.
ln fact, our entire mission could have been engineered by the Dominion.
We've been all over this ship
and we have not seen a trace of the real Ambassador Krajensky.
He was probably replaced before we left the station.
Maybe the real ambassador never came to Deep Space 9.
Everything he told us could have been a lie.
The Tzenkethi coup d'état, the threat of an attack.
And now here we are,
armed for battle and heading into Tzenkethi space.
lf we can't stop this ship before we cross the border,
we may cause a war rather than prevent one.
Which is no doubt what my people are hoping for.
A war would destabilise the Alpha Quadrant,
making it that much easier for the Dominion to move in.
lf the sensors were on-line,
it would be easier to track down the changeling.
l'm not sure they'd help.
lf you scan me while l'm a rock, you'll detect a rock.
l can't duplicate a humanoid perfectly, but l'm guessing he can.
We scanned Krajensky. He registered as human.
The changeling could be anything or anyone on this ship.
We have to narrow his options.
Confine all non-essential personnel to their quarters.
Doctor, review all the tricorder readings.
See if you can find anything. And take some security with you.
From here on, no one is to be left alone.
We have seven hours before we enter Tzenkethi space.
l want that changeling found before then.
No matter how many precautions we take,
he could replace any one of us.
We won't know it until it's too late.
Hopefully this will be over soon and you'll be able to return to duty.
Let's go.
This may take a while.
Keep your phasers on stun and stay calm.
l don't want anyone shooting one of us by mistake.
- l can't interest you in one? - l don't use them.
No changeling has ever harmed another. l'd hate to be the first.
lf we don't stop that changeling, no one will escape unharmed.
- lncluding you. - You may be right.
But l've been a security officer most of my humanoid existence.
l've never found it necessary to fire a weapon or take a life.
l don't intend to start now.
This is O'Brien. l need a security team in the engine room.
lt must have been the changeling. l went down the hall.
- When l came back... - She has a severe concussion.
We've got to get her to the medical bay.
Stay here with the Chief.
Damage control team, report to the Engine Room.
Aye, sir.
Dax is still unconscious.
She should be all right in a day or two, but until then...
ls there any way to speed up the process?
l could use a neural stimulator but that might cause brain damage.
Chief O'Brien is going to have to regain control of the ship without her.
l'm afraid so. l should get back to my patient.
The changeling's clever. Taking Dax out makes O'Brien's job harder.
One thing's for sure.
We're not going to start a war with the Tzenkethi.
lf O'Brien can't regain control before we cross the border,
l'll have no choice but to destroy the Defiant.
Find the changeling and stop him before he can do any more damage.
We'll break into two-person teams,
each armed with phaser rifles.
We've reconfigured the rifles to fire an energy pulse.
Phasers are set low enough to prevent damaging equipment,
but high enough to affect the changeling.
The changeling could be hiding anywhere.
He could look like anything.
We're going to have to sweep the ship with phaser fire.
Every conduit, every corridor.
lf he's out there, we'll find him.
- Any questions? - What if he's not out there?
What if he's one of us?
Everyone will be in teams. Keep your partner in sight at all times.
lf we see anyone without a partner?
Escort them to the brig.
Let's go.
- Let's go. - After you.
- Don't you trust me? - No, l don't.
l know exactly how you feel.
Follow me.
- Don't you ever sweat? - No, l don't.
lt's the modified phaser beam. lt's heating up the air.
This would be a lot easier if we knew where he was hiding.
Where would you be if you were him?
l wouldn't know. l'm not him.
He is one of your people.
Can't you try to anticipate his next move?
l've thought about it,
but the truth is l don't understand my people all that well.
- That's too bad. - Yes, it is.
For all of us.
Watch my back.
On three. One, two...
The changeling is in Jefferies tube 7 A,
heading to the lower deck. l'm in pursuit.
The changeling. He's right over there.
Put your phaser down. lt's me, Kira.
We got separated. The next thing l know, he opens fire.
You're the changeling. l saw you go around the corner.
l didn't see anyone.
Maybe he morphed into the ventilation system.
Or maybe he didn't.
- You may be the changeling. - Keep back.
Both of you put your weapons down.
- l can't do that, Captain. - You heard him.
What happened?
How long have the two of you been apart?
- At least a minute. - Then we've got a problem.
Any of us could be the changeling. You, Kira, Eddington, even me.
- Not you. - What do you mean?
You're bleeding.
l cut my hand when the changeling attacked me.
When blood leaves a humanoid body, it's still blood.
When part of me separates from my body...
lt reverts back to a gelatinous state.
- Sisko to Bashir. - This is Bashir.
Doctor, meet us in the mess hall immediately.
This shouldn't take long.
- Satisfied? - So far.
- Who's next? - l'll go.
l'd say the Major is exactly who she appears to be.
Try not to look so surprised.
There isn't any point obtaining a sample from the Constable.
l guess that just leaves the three of us.
Let's get this over with.
You'd better come with us.
This is ridiculous. l'm not the changeling.
lf l were, don't you think l'd put up more of a fight?
- lnside. - You're making a mistake.
Do as he says.
Would someone please get me out of here?
Bridge to Captain Sisko. Sir, we're entering Tzenkethi space.
- Any sign of Tzenkethi ships? - Sensors detect nothing.
We've altered course. Our new heading is 0-1 -5, mark 4-7.
We're headed for the Tzenkethi settlement on M'kemas lll.
How long before we're in weapons' range?
1 2 minutes.
Computer, this is Captain Benjamin Sisko.
lnitiate auto-destruct sequence. Authorisation Sisko Alpha One Alpha.
ldentity confirmed. Additional authorisation required.
This is First Officer Kira Nerys.
Auto-destruct authorisation Kira Beta Two Beta.
ldentity confirmed. Auto-destruct sequence armed.
Set the countdown for 1 0 minutes from my mark.
Authorisation Sisko 1 -5 Destruct.
Mark.
Sequence initiated. Auto-destruct in nine minutes, 55 seconds.
- Sisko to O'Brien. - O'Brien here.
l could use some good news right now, Chief.
l think l may be able to shut down the force fields
and access the sabotaged systems.
The problem is we may lose our force fields.
- Auto-destruct in seven minutes. - How long will it take?
l guess it'll have to be less than seven minutes.
That'd be my suggestion. Sisko out.
- How's Lieutenant Dax? - Still unconscious.
The changeling gave her enough sedative to keep her under for days.
She'll be out for another few hours.
- l wish l could do more. - You've done all you can.
Now it's up to Chief O'Brien.
Auto-destruct in six minutes.
All right, we're almost there.
When we set this device off,
we may lose the protective field around the warp core.
lf that happens, this room will heat up fast.
Give the warp core a wide berth
or you'll get a dose of radiation poisoning.
- Where's the changeling? - We haven't seen him.
- Wait. lt's me, Odo. - You don't say.
Chief, remember the last time we went kayaking in the holosuites?
- You had lamb stew for lunch. - That's right.
But you forgot to bring a fork. Anyone could have got that information.
Auto-destruct in five minutes.
You'd better make a decision. We're running out of time.
l've more important things to do than play choose the changeling.
Keep the phaser on both of them.
The shuttlebay doors are sealed. We have no way out.
Weapons are charged and ready to fire.
Tactical systems are programming an attack on the settlement.
- Chief, what are you doing? - Auto-destruct in four minutes.
You'll see.
Now.
Warp core field breach.
Engine room will be sealed in 1 0 seconds.
Shut down the main power grid.
No!
Engine room sealed.
Why are you protecting these solids? You don't belong with them.
- You belong with us. - Auto-destruct in three minutes.
Let go. Don't you see? You've lost.
lt's too late for you to help them, but not to help yourself.
Link with me, Odo. We can escape together.
l don't think so.
Auto-destruct in two minutes.
You've got to regain control of the ship.
Odo.
l never wanted to harm you.
- O'Brien to Bridge. - Go ahead, Chief.
l've restored control to the helm. She's all yours, Captain.
Take us away from the settlement. End auto-destruct sequence.
Authorisation Sisko Omega 1 -7 Abort.
This is Kira Nerys, First Officer. l concur.
Auto-destruct sequence aborted.
The phaser banks are powering down.
Take us home, Major.
Captain's log, supplemental. We've returned to the station.
l'm concerned about my chief of security,
who hasn't said a word since we left Tzenkethi space.
The real Ambassador Krajensky was on his way to Risa
for an extended vacation. He never arrived.
Starfleet Security believes he's been kidnapped or possibly killed.
- What about the coup on Tzenkethi? - lt never happened.
Starfleet Command wants a detailed report from each of us.
- Odo, are you all right? - l'm fine.
- l hope l'm not interrupting. - Not at all.
Captain, there's something you need to know.
The changeling, before he died,
he whispered something to me.
Go on.
He said,
'You're too late. We are everywhere.'

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