Well the scenario was the family visit, with in -depth NPCs.
Then the player said, after we did some of that, "In the tradition of the mystics of Earth, and my own people, I walk out into the desert of Ti-Vulka'ain, to begin a Spiritual Journey, logically utilizing the remaining time I have before comnpletion of my shore leave, since my family business has been thus concluded."
So I said, "You wander, and fast for days, walking among the shifting sands, travelling by night under the naked stars, and resting by day in what shade can be found. How deep will you go into the desert? (At this point, I was thinking that the character was ready to suicide by sand or something, not really sure.)"
The character said, "I walk until I find something to contemplate."
So, I just conjured up ruins, and this old shield, making it up as I went at that point. That followed with it was a warrior's shield, from ancient days. I had read the Kolinahr book, and had been thinking about doing something months down the road with Vulcan, but here it was, so I just went with it.
Instead of just contemplating the shield, the ruins, the find, for the character it became an allegory for trying to restore the past that was now dead, along with the relative.
So they returned to town, where I figured. conflict, and old shield, okay so there are these guys who would want it, to sell to some collector...
Thus next scenario I planned out the art theft ring, etc. which then grew from there, planning as I went.
Ultimately, they saw it as this shield of this warrior, even he too died, so that the character saw Starfleet as his military career, fading, crumbling into dust, with only dust and rust remaining, to be found upon the sands of Vulcan.
He said, "I do not desire my Starfleet Service to be my only legacy. I have a short time remaining, if I am to accomplish something significant to my people. Thus, I will enter the Monastery. I draft a letter of resignation, and will present it to the Captain, when I return to the ship."
So we did a stoic goodbye / farewell scene on the bridge, and a few players were upset, since they thought that the player was also leaving the group, but instead, he and I explained, no it is just the completion of this character's major story arc, only neither of us knew it at the time.
So, really, narrating is a great responsibility. From a rusted shield, ultimately this veteran of 20 missions retired. A new junior replacement PC arrived in a different department, and an NPC moved up into the vacated slot. (Since it was only a few days to travel to earth/Starfleet command to get a new officer, and they were heading that way anyway.)