"We've got to do better than this."

Phaser rifles. Lightweight, efficient, somehow unassuring at the moment. They'd been modified, but not tested.

The test was everything. The test was the future. Captain Benjamin Sisko hungered to pull the trigger, try the weapon on the creature who threatened his station. There was just no simulation for that.

His dark skin was rosined with sweat, his attitude charred. He felt the sweat and saw it reflected in glassy access portals as he crept past. They'd been at this for hours. So far, no improvements.

He paused and crouched at a junction. The space station's dismal corridors were guerrilla paradise, and that was both helpful and prohibitive. Unfortunately, given the talents of his enemy, the old station might very well aid the evil. That was the personality of Deep Space Nine. It was his to possess, as long as he could hold its slippery hand.

Dodging down another length of corridor, he glanced behind him. At his flank, the slender form of Kira Nerys was barely a sliver of shadow. Grim and focused, she was slowing down after all these hours on the hunt, he could tell. And so was he.

She was good at this, though. Of course, she had done it half her life, on the planet slowly turning nearby. But that was the past, and this was the bitter present.

Ben Sisko reached a doorway and flattened against the bulkhead on the far side. Kira did the same on the opposite side. He nodded to her, held up his hand, and counted one-two-three with his fingers. His hand closed into a fist.

The major struck the comm panel with her palm.

The door washed open and all secrets were blown.

Together they swung inside, leading with their rifle barrels. Sisko opened fire.

An expanding burst of energy flowered into the quarters, swallowing every inch from floor to ceiling, draping the walls, caressing the furniture.

After the burst, Sisko stopped, and waited. Beside him, Kira was breathing hard.

Nothing happened. The enemy wasn't here. Again.

On his heaving chest his comm badge whimpered for attention. "O'Brien to Sisko."

"Go ahead," Sisko said, unhappy with what he was going to say.

"We've swept all of level seventeen. No sign of the changeling."

"Move down to eighteen," Sisko said. That order got him off the hook of having to say he hadn't had any success either. They had to do better than this. Couldn't fight what they couldn't even find. "We'll meet you there after we finish checking the guest quarters."

"Just watch yourself, Chief," Kira said. "This changeling knows the station as well as we do. He could be anywhere. Or anything."

The painfully obvious. She was either annoyed or joking -- Sisko couldn't tell. Her voice was raspy, unreadable.

"Aye, Major."

Sisko motioned for Kira to follow. They would keep doing this until it worked. The only hard fact on their side was that the changeling had to be here somewhere. He could appear as almost any object of almost any size, but one thing remained faithfully constant -- he had to be here.

Clinging to that lacy truth, Sisko led the way to the next guest quarters. One room at a time, until they ran out of phaser power. Then it would all be over.

The next door gasped open and they charged in, but this time, before Sisko could fire, a chair -- and not a very attractive furnishing at that -- suddenly blended out of form and into a jet of red-orange protoplasmic liquid. It arched over their heads as they ducked, then in midflight changed again, this time to the form of a bird. And out into the corridor, and away.

Gone, before they could get off a shot.

Grinding his teeth, Sisko hit his comm badge. "We found him! He's headed for the Promenade!"

Together in their anger and frustration, he and Kira plunged down the corridor, trying to anticipate the moves of a creature so alien from themselves that it didn't even breathe. How could they think like that?

"This is giving me a stomachache," Kira growled as they ran. "There's got to be a better way to fight changelings."

"Obviously conventional weapons aren't going to be the way," Sisko heaved. "We have to be more creative than they are. And with beings who can turn themselves into any form, that's going to take some creating."

Wiping sweat from her cheek as they came out into the open area of the Promenade, Kira snarled, "I don't know if I'm all that imaginative."

She was furious and Sisko didn't blame her. That was fine -- he'd rather have her on his side and mad. There was too much on the line.

They came out onto one of the overhead walkways and made their way toward the stairs that led down into the main Promenade, running past two-person security teams also armed with phaser rifles.

Below, standing in front of a shopping directory, a lieutenant was joyfully directing the action, seeming to thrive in his position at the middle of action. His wavy brown hair glinted in the unaccommodating Promenade lights, and his eyes danced.

"All right," he said, "I want phaser sweeps of everything in the Promenade. He's here somewhere... let's find him. On three.... One... two..."

His mouth made the shape of the three, but his voice was choked off.

Above, Sisko almost yelled out a warning, but there was no point.

An arm came around Julian Bashir's narrow shoulders and fixed beneath his chin, then pulled him sharply off balance. The shop directory itself had grown that long arm, too late for anyone to move in. They had failed miserably, and now the changeling had a hostage.