Disclaimer: I don't own any part of the Star Trek franchise or the characters in it.
Little Ensign's Room
Chapter One: Anchors Away
It could be said that the crew of the of a certain starship could be less than observant when they felt the need for it; after all, bliss is ignorance. Or ignorance is bliss. In this instance it didn't really matter. Ignorance is always ignorance.
It all started like everything always starts, with a log entry. Someone somewhere is always making a log entry.
One particular and unfortunate crew member had at the time a conflict of interests, interests being some rather interesting stomach fluctuations and report that had been due the day before.
She took up residence in a restroom on one of the lower decks, dividing her attention between her two interests. And that's when everything happened. Well, not really, but that's when everything originally started. Or stopped. It depends how you look at it.
The close proximity of the log entry had an interesting effect on the facilities. The shade of the unfortunate crew women's uniform was also... unfortunate. But the would be no sign of anything amiss for at least the next week and no one would ever be able to trace it back to her, so none of this really matters.
It really started a week and seven minutes later when Scotty went to the men's room. But Scotty didn't actually "go" because the toilet was backed up. So he went to a different and fully functional restroom, forgetting about the backed up toilet until the next day.
And that's when, if not how, it really started.
Chapter Two: The plot thickens and we learn where exactly the Enterprise is in space...