Basically, this is part of a series I wrote carrying on from the show. I gave a copy to a friend years ago and he threatened to post it on the internet so I thought I'd save him the trouble and see what people think. It's slightly AU, in that it works on the principle that while the events of the show happened basically as described, there was a different character in command of DS9, senior to Sisko. Hopefully that's not as bad as it sounds.
Commodore's Log: Stardate 54786.2. In accordance with our treaty with the Cardassian Union, we are taking custody of prisoners that the Cardassians no longer have the resources or the facilities to keep in incarceration. The Defiant has rendezvoused with the Cardassian ship Forrez, in order for me to renew an old acquaintance.
Commodore Michael J. Billinghurst, Commander Kira Nerys and Lieutenant Ashley Reese entered the Defiant's transporter room. Michael nodded to the transporter chief. "Energise."
Two Cardassians and a human materialised on the transporter pad. Michael ignored the human for now, instead focusing on the senior Cardassian. "Legate Mandred. I never had a chance to congratulate you on your promotion."
Mandred nodded. "Central Command felt I was the right person for the job. To be leader of Cardassia is an awesome responsibility, Commodore. I am sure there are others more suitable."
"None that I can think of, Klinat."
Mandred didn't answer. Instead he held out a padd. "Your authorisation to take custody of the prisoner."
Michael examined the padd then turned to the prisoner. "Get him out of those cuffs. We won't need them anymore. Lieutenant Thomas Riker, by order of Starfleet Command, I am placing you under arrest for treason, theft and assault. Mr. Reese, take him away."
On the bridge, Doctor Julian Bashir sat in the command chair. Lieutenant Peter Barnes was working Tactical with Lieutenant Nog at the conn and Lieutenant Ezri Dax on Communications. Nog turned round. "Do you agree with this, Commander? Taking Federation citizens prisoner for crimes they committed against Cardassia?"
Bashir shrugged. "Starfleet Command's decision, Nog. Nothing to do with us poor soldiers on the front line."
"But you don't have any personal feelings on the matter?"Barnes asked. "I mean, they put this Riker chap in a slave labour camp for life."
"Then by taking him into custody we're helping him,"Bashir concluded.
"Helping Cardassians,"Nog pointed out.
Ezri glanced across. "The Cardassians are our allies, Nog. If we don't act like allies towards them, then the whole fragile trust that's holding the quadrant together could fall apart."
Barnes nodded slowly. "Last thing we want is another war. We're thinly spread as it is."
"So speaks the strategist,"Bashir observed. "Motion carried."
Reese was on duty at the brig when Kira entered. She nodded to him. "Wait outside, Lieutenant."
"Aye, aye, Commander." Reese left.
Riker stared at her from the other side of the forcefield. "I thought I saw you in the transporter room. How are you, Nerys?"
"I'm doing okay. You, Tom?"
"Not bad considering I've been stuck in a labour camp for the past six years."
"I know how that would feel."
Riker nodded. "Yes, I suppose you do."
"I'm surprised Dukat didn't have you executed."
"The Cardassians needed labour. I was as good as anyone." He looked at her. "We were right about them, weren't we? The Maquis. We said they were the enemy and we were right. Look what they've done to this quadrant with their alliances and wars."
"I never said we could trust the Cardassians."
"Oh, Commander? You were the Federation uniform now, I see."
"Bajor's a member of the Federation now."
"Ah. And they have no problem allying themselves with people who sold out Federation citizens to the Cardassians once before? Because it looks to me like they're doing it again."
Kira sighed. "We just do what we have to do, Lieutenant. I told you once that terrorists don't get to be heroes. You certainly don't."
Michael was in his office when Commander Elizabeth Shelby entered. "We're on our way back to Deep Space 9, sir."
"Thank you, Commander." Michael paused for a few seconds, noticing that Shelby showed no indication of leaving. "Was there anything else?"
"Lieutenant Riker. Do you really think he's done anything worth punishing?"
"He nearly set the Federation at war with the Cardassians. If it hadn't been for me, he'd be dead. I think I've given him all the sympathy he deserves."
"We ended up at war with them anyway."
"It's not the same, Liz, and you know it. We fought a war with the Dominion, who the Cardassians just happened to be allied to. If we'd fought them alone, then once it was over the Dominion could've just flown in with fresh troops and taken us all over. And don't forget it was the Maquis' constant attacks that weakened the Cardassians and caused Dukat to strike a deal with the Dominion in the first place."
"Bit black and white, Commodore. It was the Klingon invasion and the destruction of the Obsidian Order just as much."
Michael sighed. "I once made a promise that I'd put an end to the Maquis. I was unable to keep that promise. I'm not going to make that mistake again."
Kira sat in the command chair on the bridge, while Bashir worked sciences. Barnes, Ezri and Nog continued to work tactical, communications and conn. Ezri looked round from her panel. "Commander, I'm picking up a distress call. It seems to come from a Federation civillian ship. They say they've suffered asteroid damage."
Kira glanced round at Barnes. "Can you fix their position?"
"Within a few thousand kilometres."
"Well, I guess we'd better take a look. Mr. Nog, lay in a course and engage at warp three. Commodore Billinghurst to the bridge."
Two hours later, Michael paced back and forth on the bridge as the Defiant approached the co-ordinates. Kira had taken the helm while Nog worked engineering and Shelby handled weapons. He glanced over at Barnes. "Anything?"
"I'm detecting the vessel 1500 metres off our starboard bow."
"On screen." Michael glanced at the image. "Hail them."
Ezri adjusted the controls then looked round, puzzled. "No response."
Bashir was examining his panel, curiously. "This is odd. I'm not detecting any sign of damage. And the ship seems to have been modified – it's carrying phaser cannons of some sort."
Before any of them could digest this information, the civillian vessel turned and fired on them. "Shields up!"Michael ordered. "Red alert!"
"They took out our generator,"Nog observed. "We haven't got any shields."
"Evasive manoeuvres, Kira,"Michael ordered. "Commander Shelby, return fire."
Outside the brig, Reese turned to a security guard. "Watch the prisoner. I'm going to the bridge."
Before he could move, though, there was the hum of a transporter. Two men and a woman materialised, carrying phaser rifles. They shot both Reese and the guard before they could move.
One of the men – Tando – operated the controls to lower the forcefield. Riker looked at them quizzically. "What's going on?"
"We're getting you out of here." Tando slapped a locator on Riker's sleeve then spoke into his communicator. "Four to beam up."