Star Trek AOS: Nightmare Mate

You've read the version where Serenity met Jim at an early age and became siblings. But what if they didn't meet until the Academy, where Serenity returns from her anomaly duties to teach magic defense classes. Spock learns that he must share his classroom with a strange woman, whom he at first believes to be an illogical human. Jim flirts with Serenity everyday, and every time she says no. One day Spock stumbles in to her class from following Jim. His memory of her is restored, now that their paths have crossed once more. He finally remembers her as the young girl he used to be friends with on his home planet Vulcan. He learns she is the one his Vulcan heart and soul has been missing.