A/N: Third teaser for my upcoming series "The Enterprise and the Doctor".

Disclaimer: I don't own Star Trek, nor Doctor Who.

Chapter 1 - Briefing

Personal Log, Gariff Lucsly, Stardate 27050.41. We have left San Francisco on the Falco, en route to Al Rijil VII, on an impromptu mission for the Department. I was forced to give up the plans for my upcoming leave when the message arrived, since I was the only other agent on call besides Agent Bel, after many agents, including my partner, went down with Zek flu and were quarantined. Agent Bel has just called a meeting, when I expect her to finally lend me the briefing papers which were somehow missing from my orders.

Stardate 27050.43 - Starship Falco's briefing room

Agent Gariff Lucsly, of the Federation Department of Temporal Investigations, entered the briefing room early for his upcoming meeting, only to find Agent Bel already there. She acknowledged his presence with a minute nod towards one chair on the other side of the table, and continued working on her PADD. Lucsly dropped his own PADD on the table and sat with trepidation. Unscheduled missions like this one almost always meant something very wrong, and possibly very dangerous, had already happened and it was up to them to handle the consequences. In a way, he was lucky to be here, with one of the most experienced agents of the DTI. As a junior agent, he could use the opportunity to learn how to deal with situations like that. But that doesn't mean he had to like it.

Besides, he dreaded having to work with the unflappable Tozenor again. Last time he had almost lost his composure after the infuriating senior Agent, on the post-mission debriefing, had meticulously commented on how each one of his actions and decisions had somehow fallen short of his 'potential'. He had to admit, grudgingly, that she had been mostly correct, and he did take advantage of her input later on, but her patronizing ways were rather difficult to bear.

At exactly the appointed moment, his tall dark-skinned humanoid partner, with her deep black eyes and elongated face, lowered the PADD and stared at the younger agent. The top of her head was covered in a blue-grey fuzz, which descended to her neck and shoulders down the outside of her arms. She was dressed in the regular grey uniform of a DTI agent, but lacking sleeves, so her arm hair could be seen, forming tufts at the elbow.

"Welcome, Agent Lucsly. I gather you haven't been briefed on the details yet."

"No, ma'am, all I know is that we have to be on the central marketplace of the city of Tennaa, on the southwestern continent of Al Rijil VII, on stardate 27053.8." That was why they were aboard the Falco, a small, fast courier assigned by Starfleet to the DTI for exactly these kind of missions. Otherwise they'd be going on a much slower runabout, and take one week or more on each leg.

"Precisely. It's a Code 17. I assume you are familiar with Special Code missions?"

Lucsly blanched, but otherwise kept strict control of himself. "Yes. I've been to three Special Code missions already, but none of them was a Code 17. How many Codes are there?"

"No one knows. Some suspect the Velarii add new Codes as they deem fit." She might have smirked at that, but Lucsly was uncertain. A Tozenor's facial expressions were often quite difficult to interpret. "But Code 17 is a relatively common one. I've been to a few of them myself."

He inwardly shuddered. The Special Codes were brief messages received from their mysterious allies through the temporal communicator device installed in the DTI Headquarters. They consisted only of a numerical code plus temporo-spatial coordinates, most of the times with just a few words added as a side note. The code was a reference to a prepackaged briefing, containing all the background a DTI agent would need to deal with a given situation, while the note, when present, would give the specific context with maybe a hint to guide the agents on the possible alternatives. The Velarii apparently were unwilling to give too much information, instead trusting the DTI agents to use their own judgment on the matter. It was one of the few things Lucsly appreciated about their alliance.

Since Agent Bel didn't seem to be going to volunteer more information, he decided to forge ahead with questions.

"What is a Code 17, then? Not a spacetime rift." That one had been frightening, but ultimately straightforward. "A lost artifact, maybe? Sorry, these are Code 2. I've been to one, already." It had been the most adventurous mission Lucsly had had up to that moment, what with the smugglers, pirates and the odd temporal agent all trying to take possession of the artifact and prevent the others from getting it. He'd be happy if he never had a mission like that again.

"Codes 10 and 12 deal with artifacts as well, but no, Code 17 is about tracking down an individual."

"A person. A dealer on ancient temporal artifacts?" She didn't blink, but frowned minutely. "A survivor from a time-displacement event?" No change. "A rogue temporal agent from the future?" All cases which would readily fall under DTI jurisdiction, the last being one of the worst threats the DTI was meant to fight and Lucsly's personal nightmare. Nearly as worse as a certain reckless Starfleet captain with way too many temporal violations under his belt.

"Neither. He's an alien renegade, of an unknown species, who sometimes drifts into Federation territory."

"A... renegade," he stated, struggling to keep his face impassive. Well, at least he's not a time-traveler.

"Most likely from a very advanced civilization, who can come and go as he pleases, without being intercepted by Starfleet."

"That doesn't explain why we are charged with dealing with him, instead of the diplomatic corps. Or, say, Starfleet Intelligence."

"The reason we are charged with, as you say, 'dealing' with him is that the Velarii are very interested in his comings and goings, and especially to ensure that no one tries to detain him."

"Why?"

"He may be a renegade, but they believe his people probably continues to keep tabs on him from time to time and they might decide to come looking for him if he suddenly disappears. That would be very bad," she said.

"So the Velarii probably know a lot more about him and his people than they are willing to tell us." He really wished the DTI wasn't the only Federation outfit the Velarii seemed to tolerate.

"That's a given. Anyway the Federation has already tried to capture the Doctor twice."

"The Doctor? But wasn't he-"

"The second time," she interrupted him, "the Velarii themselves intervened. The Federation might have been destroyed that day if it weren't for them."

Lucsly felt the chill on his spine at the thought. There were a lot more dangers to the Federation than the common citizen suspected. And at least a few of them came from such unfathomably alien advanced civilizations who either ignored their existence or dismissed them as unimportant. It was for reasons such as these that the alliance with the Velarii was valued and kept, in spite of all the stresses and difficulties.

"But he continues to visit us, even after that."

"He's a very... unusual... individual," she said. She would know that, having met him before, but Lucsly could only guess at what she meant by that.

"If I remember well," and of course he remembered his extensive studies of the infamous Starfleet officer, "James Kirk met the Doctor a number of times during his five-year mission as captain of the Enterprise." The problem was that that summed up almost all the information on him available to the public - and to junior DTI agents. So Lucsly was curious, in spite of himself.

"Indeed. As I was saying, the Doctor is not hostile to us, quite the contrary. He may not be very fond of Starfleet, or of us, but on occasion he has availed himself of our help or even offered his own. Both then with the Enterprise, and now, when our agents are tasked with following him. Note that," she continued, before Lucsly could interrupt, "he will certainly detect our presence almost immediately, even before we manage to identify him. And he'll try to evade us. It's our job to avoid scaring him away while staying on his tail until we can complete our mission."

"Which is?"

"Find him, follow him, figure what he's up to this time, ensure that no one else tries to interfere with him, and stick with him until he leaves." She stopped but Lucsly knew it wasn't all.

"There's more," he said.

"Quite. There's also the special instructions." She paused, but this time Lucsly waited for her to continue. For once her smirk was recognizable enough. She finally said, "We are to deliver an object to him."

"Object? Which one?"

"This container," and she showed him a cylindrical container approximately thirty centimeters in length by eight centimeters in diameter. It was a dark grey object, decorated in silver whorls with intersecting lines, apparently made of some sort of metal, with no visible seams. Lucsly examined it. "It materialized along with the message," she said, motioning to her PADD, where he could see the received message in bright orange. "It's supposed to hold some sort of warning. We are to deliver it and wait until he has opened and read it, then protect him until he leaves."

"Protect?" He picked up the PADD. The translated message was terse, '17. Deliver admonition, safeguard subject'.

"Unusual, yes. But he does have a number of enemies."

Lucsly frowned. "We are not security guards."

"Nonetheless, that's our assignment. I'll talk to Captain Reginald, they can lend us a security detail."

He huffed. Definitely not a regular mission. He wondered if it could get any worse.

A/N: Agent Lucsly has only had a brief appearance on the TV, on the famous Deep Space Nine episode "Trials and Tribble-ations", but he and the whole of DTI are greatly developed in the Star Trek: Department of Temporal Investigations novels by Christopher L. Bennett. If you liked this story, or if you just like stories about time-travel-related problems, you'll probably enjoy his books.

I've invented the Tozenor specifically for this story, as yet another humanoid civilization within the Federation. I have developed a reasonable backstory for them, and they may appear again later, but there'd be very few individuals employed by the Federation outside their home systems at any one time, so they shouldn't be very common.