What is it, exactly, that constitutes a person? Is it their memories and experiences, or something more, something independent and unchangeable?
What is the soul, and what makes one different from any other?
A mission-gone-wrong results in Spock!Prime transferring his katra to his younger counterpart. How will the Vulcan healers be able to differentiate between two very similar (if not identical) katras? And how will this transference change the way Spock perceives his own reality?
Spock must start questioning his own perceptions, reactions, thoughts and/or feelings while his older counterpart’s katra is inside him. Does NOT have to be a romance fic.
Bonus points if:
1. Spock and Uhura are still in a (real, full-blown, happy(ish)) relationship when the transference occurs
2. Spock genuinely feels torn between his feelings for Uhura and Kirk
3. Spock questions whether the love/lust he feels for Kirk is (solely) the result of holding Spock!Prime’s katra
4. It is uncertain whether the healers are able to fully remove Spock!Prime’s katra (OR)
5. The katra they removed was the wrong one (OR)
6. The two katras intergrate into one
In The Search for Spock, the concept of “Katra” is very vague. They call it a “living spirit,” “eternal soul,” and “…everything that [Spock] was…Everything he knew.” Have fun with the ambiguity.
I would strongly suggest watching or re-watching The Search for Spock before attempting to write this story.