A very interesting start. The introduction is fascinating, the Xenarth portrayed as a genuinely alien race, but with characters and motivations we can understand. Then we get to the Lexington, encountering one of those 'space phenomenon that knocks the ship about a bit and kick starts the plot' events that are used so often on Trek. But they're used for a reason. They work. And now the ship has to investigate, even though there are---very believable---reasons for the crews reluctance.
I'd also like to praise the depiction of Kettaract. Another Star Trek trope, the guy who's assigned to the ship for an important project and manages to annoy everyone, it would be easy to present him as a cardboard cliche. Yet, even in this short appearance, there's a touch of depth to his characterization.
One slight quibble. In the following exchange:
“If we get any closer to where you have us go we’ll be right in the Romulans’ backyard. We might as well wave a flag and say here we are, come and take a shot at us,” responded Terrence Lawford in a crisp English accent.
The middle-aged molecular scientist glared at the navigator. “If that’s where my readings take us than that’s where we have to go,” he shot back. “Romulans or no Romulans.”
“Doctor, we all appreciate the importance of your work –“
“I am seriously beginning to question that you do.”
The way it is written, it looks like the line “'Doctor, we all appreciate the importance of your work –“
' is spoken by Lawford. So the reference to a 'burly Russian first officer' in the next paragraph is rather confusing, especially as he isn't named until several paragraphs later. I was able to work it out, but it did rather interrupt the narrative flow for me.
That aside, a very good start. I'm looking forward to more.