Rating: All Ages
Author's summary: Romana finds that her tastes have begun to change.
Characters/Pairings: Romana I/Fourth Doctor, K9
Warnings: none that I can think of (unless you want me to warn for Classic Who)
Recced because: Of the two Romanas, Romana I definitely gets the less play in fandom. Is this because Romana's first incarnation was so standoffish? Less blond? Less overtly shippy with the Doctor? Probably the most likely explanation is that while fic with Romana II has her whole life ahead of her to play with, Romana I only really had the Key To Time Arc. Whatever the reason, it's rare to find well-written fic with Romana I in it and the fact that "Threads" is so very much more than just well-written makes this fic a joy to rec.
Vali takes Romana as we first meet her--a prissy young know-it-all straight from the Academy--and shows how she grows and changes over the course of the search for the Key To Time. It's a character study, but it's also a love story--or, rather, a falling-in-love story--between Romana and the Doctor. We see him through her eyes, nothing more than a crazy old vagabond at first and something altogether different at the end. There's also a good deal of commentary on Gallifreyan society, which sheds some light on why Romana might have chosen to regenerate at the start of S17.
In short, "Threads" is a real treat to read.