The very nature of ASHER's programming hated problems. From variations in his basest of binary cycles to the still un-replicatable subroutines that gave him sentience, his entire being depended on flawless execution of millions of tasks at a time, without variation, without problem.

And he had spotted a variation. It wasn’t a big one, but it was a problem and one that he needed to investigate.

He was in command, half way through Gamma shift or ‘blue period’, Starfleet’s ship-friendly way of saying ‘Time of night when even the graveyard shift starts to yawn.’

ASHER, who normally plugged himself into ships computer when he was off duty, had set his emitter to activate his conscious subroutines in the event of a variation - which they had done, roughly ten minutes ago.

He sat at the helm, the lights still dimmed for the comfort of the rest of the crew. His hands were motionless, folded in his lap as he interfaced directly with the console. He shook his head, squinting slightly, the mumbling subroutine Chu had helped him design kicking on. "Still a point 1.34562 variation in mass..."

"Mass of what?" A voice asked from behind him.

ASHER did not even look up, automatically recognising the voice from the ingrams in his memory banks. "Commander. You have not received the regulated eight hours of sleep as mandated by Starfleet."

He heard Chu yawn, then say. "You're telling me. Couldn't sleep."

ASHER turned finally, allocating twelve percent of his functions to interacting with Barker.

Barker sat down at the ops station, still in regulation PJ's, and yawned again. "The engines...feel...wrong."

ASHER nodded. " My point exactly." He blinked and the console behind him chirped, sending a copy of its readings to the console Barker sat behind. "Since we have entered the slipstream, the Hellcat has had to alter its subspace wave by roughly two percent every 12.4563 seconds to maintain the stream."

Barker nodded slowly, trying to concentrate on the screen through sleepy eyes. "This kind of variation only happens when mass outside the normal drive bubble is present. We didn't bring anything along..."

ASHER nodded again, turning back to the helm and tapping in a few more minor commands, when Barker spoke.

"ASH, whenever you were working with Project Sign, monitoring the mirror universe, did you ever send probes through ?"

ASHER, again not turning, nodded slightly. "Of course. I was in charge of masking their signature for most of my dur..." ASHER paused. "I believe I see your point, Commander. I’ll attempt to adjust the sensors to accommodate possibility, the modifications will take approximately fifteen minutes."

Barker blinked. " That long?"

ASHER’s normally stony face seemed to be just a bit smug. "It was a rather...complex.... assignment."

Barker sat in silence, listening to the myriad chirps and beeps as ASHER did his work. He decided to leave ASHER to the modifications, if he wasn’t going to get any more sleep, he might as well get changed.

Finally, after what seemed like more that fifteen minutes, yellow alert sirens started to blare. ASHER nodded to himself and remarked. "Clever."

"What’s clever ?" Lieutenant Commander Barker enquired as he re-entered the Bridge area. "What is it ?" He asked, placing his hands on the back of the Helm chair, looking at the screens and console over ASHER's shoulder.

"We’re definitely been followed by some kind of probe. A modification of my own design to ‘hide’ the probe we sent to the mirror universe to be exact." ASHER remarked. "The probes is utilising a replicator to match our exact temperature linked to the drive plasma and it’s all integrated into the navigational shields, rendering it .."

"Virtually invisible to our sensors" Chu interrupted.

"Exactly" ASHER grimly agreed.

"Origin of the probe?"

"I would say it’s one of ours, probably the one we launched to track the ISS Leviathan, sir. But this kind of masking has, to utilise an axiom my fingerprints all over it. There’s only one ‘person’ who could have achieved this, the mirror ASHER, he’s the one who altered and redirected this probe." ASHER remarked. "The plasma drive design was originally from a Preserver data core that was found about the same time I was. Starfleet had spent years trying to decipher it, until I joined ‘Project Sign’. Within three months we had a working prototype and we had a full operational probe within six."

"Which means..." Chu paused, shaking his head

"Yes, sir. We’re been watched and more than likely for sometime. The mirror vessel could be either right behind us or could even be waiting for us at our destination."

Chu sighed, sinking into the command chair. "I doubt they'll bake a cake."

ASHER blinked, tilting his head to the side. "You are most likely correct sir. It is far more likely they would replicate one - though why our arrival would warrant a celebration is unknown."

"ASHER ?" Chu said.

"Yes, Commander?"

"Find out how to get that tail off the donkey." Chu requested.

"Yes, Commander." ASHER replied.