Their rescue pod was hailed by the shuttle Galileo. Kirk took the call. "Rescue pod fourteen here. What is it?", he asked. "For god's sake, Jim. For a while we thought you were dead.", McCoy grumbled through the speaker. "Is the hobgoblin with you?", he continued. "I am present.", Spock spoke up from behind his blanket.

Yesterday

Per McCoy's apprehension, it had gotten worse. A crate had fallen on a Crewman who had been on the Storage Deck, taking inventory. Luckily, he could be saved, but Bones was fuming with anger. "Goddamnit Jim. What are you waiting for? Does somebody need to die before you can order a search for whatever is causing this?", he hurled at the Captain who had just entered his office. "Tell me what they should search for.", Kirk retorted, slightly agitated himself. "I don't know, have the Vulcan think of something." Kirk breathed, calming himself. "I keep wondering if maybe all this is just imagination and technical failures. People hear other people speak about the ghost they've seen, and suddenly they see it too.", he explained.

McCoy sat down behind his desk. "Look, it's simple. If you have the security team search and they find nothing, you're an idiot. But if you don't let them search and there is indeed something, and I know I'm right, you're not only an idiot, but also probably dead." McCoy looked him straight into the eyes. The Captain sighed. "I guess you're right.", he conceded. "We will have a meeting in half an hour to discuss the situation.", Kirk decided. Bones nodded contently.

To his dismay, Kirk found that it was already early afternoon. He had spent most of the morning on the bridge and in the astronomy lab. The sensory array had been repaired during the night and Kirk needed to decide, together with his Science Officer, which parts of space to leave out of the mapping process, as they were behind schedule and their next mission was already assigned. After that, he had a video call with Admiral Nogura, in which he had to explain why no maps had been transferred the day before. Then, he had let Chekov come to the bridge for a course correction according to the specifications he and Spock had decided. A bit later, McCoy had wanted to speak with him.

And now he was standing in the corridor outside Sickbay. He moved to the nearest intercom unit, and pressed the button. "Captain to all senior officers. We will meet in the conference room in approximately thirty minutes. Kirk out.", he spoke into it. That done, he went to the Mess Hall, as he hadn't eaten anything all day.

The bridge officers looked at him, all appearing rather concerned, or, like in Scotty's case, very tired. "Gentlemen, we have an intruder aboard.", Kirk stated, looking around the room. "This creature is potentially harmful and can make itself invisible. Any suggestions on how we could catch it?" Everyone seemed to think for a moment. Spock spoke first. "If it is indeed a lifeform, it will radiate energy of some form. This signal could be tracked by our tricorders.", he suggested. Kirk nodded. "But how do we know what kind of signal that thing sends out?", Chekov asked from his place next to Wendy. Now it was Scotty's turn to say something. "We can just eliminate all known frequencies and see what is left.", he proposed. "It will take some time.", Spock considered. "Well, then.", Kirk interjected. "You better start immediately."

And so, they did. Spock and Scotty went to reconfigure a tricorder so it would detect the unknown lifeform. First, they eliminated all the frequencies Scotty's machines and tools sent out, after that, all humanoid life signs. Spock took the tricorder to the hydroponic garden and to the biolab, to filter out the rest of the life signs as well. That finished, he brought the device to the bridge, where Kirk was waiting for him.

"We have a frequency.", Spock reported and gave the tricorder to the Captain who was sitting in his chair. "Very good.", Kirk praised. He looked at the displayed frequency. "That is nothing we have encountered yet, have we?", he asked his First. The Vulcan shook his head. "I cannot even tell you what this life form is based on.", he admitted. Kirk looked at the Commander and smiled. "Fascinating, wouldn't you say?", he asked. "Yes. But also, very concerning." Kirk knew Spock was right. He hit the intercom button on his armrest. "Kirk to Giotto.", he announced. "Giotto here.", he was answered. "Mister Spock has determined the energy frequency the intruder emanates. Have your people search for it.", Kirk ordered. "Spock will send you the frequency.", he added further while looking at his Commander at the Science station. Spock nodded and pressed some buttons on both the station and the tricorder. A few seconds later, Giotto spoke again. "Data received. We will begin with the search immediately.", he acknowledged. "Make it so. Kirk out."

While the Security team was doing their work, Spock stayed at his station and did some research on the energy frequency he had found. Kirk stayed in his seat and watched his efforts. The longer Spock searched, the more his face displayed the slightest of frowns. "Something wrong, Mister Spock?", Kirk asked. "Not inherently wrong, merely curious.", the Commander replied. "What is it?", Kirk wanted to know. "There is no entry on our computer referring to the frequency." "That's strange.", Kirk remarked. "Any idea why?", he added. "The frequency is somewhat similar to the one that warp engines sent out. It is possible that it has been recorded before but mistaken for the engine's."

They spent the rest of the day waiting for the search's result. During the afternoon, Spock returned to the Astronomy lab to check on his underlings. Giotto reported once in a while. Every time they thought they had caught on to the signal, it suddenly appeared a few decks under or over them. Once in a while, it disappeared completely for a few minutes. When it was almost twenty-two hundred, Kirk decided to beat it for the day. The Security had already been replaced by the next shift, but there was nobody to relief the Captain. He took the turbolift to the Science Deck, as he wanted to make sure that Spock would sleep as well.

"I do not require as much sleep as humans do.", his First complained. "Half-human.", Kirk reminded him. "Also, I know that you ended up helping Scotty last night." The Vulcan seemed a bit surprised by the last sentence. Kirk sighed. "Go to bed, Commander. This is an order." "Very well.", Spock conceded.

Kirk didn't know why, but somehow, he had snapped awake. Had he had a nightmare? He couldn't remember. A short glance to the clock confirmed that it was only four-hundred, therefore not yet time to get up. Kirk decided to get something to drink. As he drank a glass of water that he had just filled in the bathroom sink, he thought he heard something through the bathroom door to Spock's side. A small sound, repeated over and over and over. Was Spock alright? Maybe he was having a nightmare. Did Vulcan's have nightmares? He decided to knock on the door. "Spock, you alright?", he asked. No answer. The sounds continued. Worried, Jim entered his friend's quarters. At first, he couldn't believe what he saw.

Spock was in his bed and under his blanket, slightly moving as he made the sounds that Kirk had heard through the door. He indeed seemed to have rather violent nightmare. But this was not what had Kirk freeze in place. Over his First Officer, there was something he could only describe as an oily cloud. It seemed to continually turn itself inside out. Sometimes bubbles formed and burst, making the thing look like an oversized black soap bar someone was treating rather roughly. It floated through the air like it weighed nothing.

Breaking from his trance, Kirk rushed over to Spock and shook him, trying to wake him. The cloud came nearer and Jim could feel its cold. "Spock, come on. Wake up.", he urged his friend. Panic rose in him. Finally, Spock opened his eyes, looking at him in perplexity. "Jim?", he asked, his voice cracking. "Do you see that thing?", Jim asked and pointed at the cloud. Spock's eyes widened a bit and he immediately entangled himself from the blanket. He grabbed his Captain by the shoulder and pulled him into the bathroom. Kirk didn't struggle. "What was that?", Kirk asked. "The creature, I presume.", Spock stated, still breathing rather heavily. "It's the black cloud you told me from!", Kirk realized. For a moment, they were just standing there, not knowing what to do.

Spock glanced at the door to his quarters. A piece of the cloud was already pushed through it. "It can move through walls.", he remarked. They moved further in the bathroom, away from the door, until they were standing in the sonic shower. The cloud was now completely inside the bathroom and floating menacingly to their position. Suddenly, Spock was fiddling over his head with the sonic shower's particle extruder. "What are you doing?", Kirk asked sharply. "I have found that the extruder is somewhat loose.", Spock gave as a way of explanation. "Spock, this is no time for repairs.", Kirk scolded. "I am aware.", Spock commented, now holding the cup-shaped object in his hands. They could see the black cloud reflecting in the metal's smooth surface.

By now, the cloud had come incredibly close. Spock swung his arm in a fast movement, holding the extruder in a way that the opening looked in the ground's direction. The cloud turned dark red and lost somewhat in size. Suddenly, it disappeared through the ceiling. "I have a piece.", Spock calmly stated when they were alone. He showed Kirk the little piece of cloud that was inside his makeshift cup. It didn't move anymore.

They were currently walking as fast as possible without actually running. The biology lab was dead ahead. "How did you know that this would work?", Kirk asked his First, slightly breathless. "I had no certainty on that matter. I have however noticed that the occurrences started with the forceful opening of the high security box in Engineering." "I don't understand.", Kirk stated. "The inlay of these type of boxes is made out of titanium, as are some parts of our sonic showers." Now Kirk understood. "You think that that thing can't go through titanium!", he exclaimed. "It obviously cannot.", Spock agreed. Now they had reached the lab. First thing, Spock moved the piece from the extruder to a container from titanium.

Kirk was assisting his Science Officer when McCoy entered. "What's going on?", he asked, grouchy as always and also quite tired. He didn't even realize that his superiors were both wearing sleeping attire. "The analysis of the intruder's biology will soon be finished.", Spock told him. "Did you finally catch that darn thing?", Bones asked. "Only a part of it.", Kirk confessed. "Huh?", Bones sounded and came a bit nearer so he could see. Just then, the computer sounded that it had finished the analysis. Spock took the data card out of its receptable and put it into a nearby PADD. As he began to read, his eyebrows moved upwards.

"What is it?", Kirk wanted to know, slightly excited. "The lifeform is carbon-based." "Carbon-based?", McCoy asked, incredulous. "I have never seen or heard from a carbon-based lifeform that could defy gravity.", Kirk remarked. "It is a most unusual creature.", Spock replied. "Every cell on, what I can only describe as, 'its skin' has an organelle that is able to receive energy transmissions." "What would it do with them?", Bones asked. Spock looked at him directly. "These types of organelles are typically found among telepaths. These are, however, slightly different. I speculate that the lifeform may consumes the energy waves emitted from brains."

"Why would it scare us, then, when it could just suck up our brainwaves?", Bones wanted to know. "Doctor, as you are certainly aware, strong emotions produce a higher volume of energy emission. It would only be logical for a creature such as this one to develop a strategy to incite such emotions in its victim." "And strong negative emotions are probably easier to provoke than strong positive ones.", Kirk added. Spock nodded. "Now that we know all that, how do we get rid of it?", Kirk asked and looked at his two friends in contemplation.

Author's note: Woah, you made here! The secret has finally been lifted. Make yourself ready for the finale…