"Ensign Jones?" Nurse Flynn smiled with gentle concern at the young woman poking at her replicated peanut butter sandwich. "You're quieter than usual, dear. What's wrong?"
Agatha Jones shook her head. "I don't know, really," she confessed. "I keep having these strange dreams where I have a sister who gets taken away by people wearing black, but... I'm an only child."
Nurse Flynn hummed thoughtfully. "When did you first start having these dreams?" she wondered.
"About a month ago?" Agatha frowned, and then sighed. "I first thought it was because of the transition from the Academy to the Enterprise. Stress nightmares would've made sense, right?"
"Indeed they would." Nurse Flynn took a sip of her own tea. Replicators never seemed to capture the exact taste of her favourite blend, so she would try to get packets of it whenever she was on shore leave. "Not to mention you being assigned to different ships from your Academy friends. I can imagine that being difficult."
"For some reason, most of my Academy friends have always been older students." Agatha shrugged. "Holly Marshall and Hannah Klein graduated before me. We sorta keep in touch. Work's been overwhelming lately, though, so they haven't really been online."
"Have you told anyone else about these dreams?" asked Nurse Flynn. "Or recorded them in a journal or something?"
Agatha took a bite of her peanut butter sandwich, wrinkling her nose a little at the muted flavours. "No," she admitted after a moment. "It hasn't affected my performance yet. I just... I don't know. I feel like there's an entire part of my brain that's locked up to me, and these dreams are telling me something about it. I don't think digging into it is a good idea, and yet part of me wants to. You know?"
Nurse Flynn nodded. "It could be how your brain is trying to parse a buried traumatic memory," she said gently. "I'd talk to our ship's psychiatrist about it, if I were you."
... And then there's this entire thing where Agatha Jones, only child of Jack and Cynthia Jones (Cynthia in particular having disappeared unexpectedly during Agatha's first year at the Academy), ends up reconnecting with Hannah Klein, who, according to their social media accounts, had been a good friend of Agatha's up until Cynthia's disappearance, and then inexplicably stopped hanging out with her. Hannah and Agatha dig into the fact that Agatha's been having these dreams about an older sister getting taken away by what was basically the Men in Black, and discover a network of people in Starfleet who'd had close encounters with the Men in Black but can't seem to recall exact details. Sort of like how the 21st century had people claiming to see "cryptids" like Bigfoot or getting "probed" by little green men who are most definitely not Vulcans!
Oh, and also, some older people in the Academy swear there used to be an apartment complex near campus called the Declor building, but there is no record of the Declor building and it certainly did not burn down sometime around Cynthia's disappearance.
Agatha and co are from a missioned fic taken on by Eledhwen and Christianne in 2014. I picked this one since it had the widest variety of named side characters, some of which aided and abetted the Sue, but were still spared by Eledhwen and Christianne. Plus Star Trek being the origin of Mary Sue in general means there's probably decades of close encounters with the PPC!