The captain had been gone for exactly 3 days by the end of Spock's communiqué with Commodore Gregson and the Enterprise was tense with worry.
Normally, when the captain went on shore leave, he would disappear for a day or two, sometimes with Doctor McCoy, or sometimes alone to enjoy himself without worry. However, it was unusual for the captain not to warn them before taking off. Yet, despite this anomaly, Spock had allowed approximately 13 hours after the first 48 hours of the captain's leave to pass without concern.
It was only after 13 hours that both he and the Doctor started to grow worried. The worry soon spread to the bridge as crew members returned dutifully to the ship and the captain still didn't answer repeated hailings by Lieutenant Uhura.
By the fifteenth hour of the day, Spock alerted the space station and several suspects were detained by the ever-efficient commodore. Meanwhile, the ship beamed down several security officers to search on foot while the bridge crew continued to try to contact the captain.
Fifty minutes before Spock contacted the commodore, Captain Kirk's communicator and phaser were found in the conservatory. All pretence of remaining calm fled the doctor, forcing the first officer to remove his friend from the bridge.
After the short discussion with the commodore, however, the tension lessened slightly as Spock ordered Lieutenant Sulu to commence a scan of the station. There was a possibility that such a scan would be ineffective, but every option had to be explored and done in the most efficient manner possible. If all else failed, then they would have to resort to other, more creative means. He knew such measures would been taken by his captain if it were that was Spock missing instead.
--
A day passed in awkward companionship between captor and captive. Gregson had left Kirk alone in the room after the call and returned the next day to share three meals with the captain, chatting away on subjects of no consequence with him, as if they were two friends on shore leave. However, despite this companionship, Kirk was still very much aware that that other was waiting for him to lower his defenses and strike.
Although it was one of his more comfortable imprisonments, Kirk found himself dreading what was to come moreso than if he'd been locked away in a medieval dungeon. What worried him even more about his present situation was that the Enterprise had yet to locate him. His transponder was still in his forearm, but it seemed Spock's scan hadn't picked it up at all. Clearly he was in a building that somehow managed to block scans altogether. Gregson had planned it well.
--
The first scan had shown nothing. The second scan was the same. Altering the systems slightly, still nothing. It made Spock uneasy and suspicious. Even if the transponder were destroyed, he should be able to pick up faint signs of it...but every scan brought up absolutely nothing.
Perplexed, he withdrew to his quarters after his shift to meditate, ordering Sulu to send him the exact results of the scan.
After forty minutes, the Vulcan found himself unable to reach even the second level of meditation and got up from his place before the firepot to review to scans.
Reviewing the results on the screen with a wrinkled brow, he typed in several commands to extract and magnify certain anomalies.
Within five minutes, he realized just why the Enterprise couldn't pick up the transponder signal: there were several buildings meant to house the most classified personnel and information of Starfleet on Starbase 70 that would stop any scan from probing into their interior. Discovering this, he allowed himself to feel a few moment's relief that the first obstacle of his search was gone.
The moment passed quickly and soon he switched on the comm and ordered Uhura to patch him through to Commodore Gregson.
--
Kirk woke up to the sound of voices outside his room. Blearily, he looked at the head's clock and noted that it was 0400 hours. Slipping out of bed, he padded over to the door to listen, smiling when he heard Spock's voice.
"Commodore, I understand that it is against regulation to search all three buildings, but I must insist—"
"Denied, Commander. You know I can't allow that and I don't believe anyone in any of those three buildings would be holding Captain Kirk. In fact, I made an inquiry already and he isn't in any of them."
"Nonetheless, I request permission to do a personal investigation. It is imperative that we recover the captain."
"I will conduct a second search, Mr. Spock, despite my doubts, and give you word tomorrow."
Kirk closed his eyes, imagining the stern expression on his exec's face as he stared down the commodore in the continued silence. He knew Spock would willingly break regulation to get him back. It was only a matter of time. Gregson had no idea who he was dealing with.
With that in mind, he quietly went back to sleep, knowing that it was best he was well-rested for the day ahead. The commodore was going to prove troublesome now that he was cornered.
