Fact: I’ve been searching The Society library and there is no information about unicorns (aside from the Siberian Unicorn).
Fact: Upon leaving the library this morning, I was presented with this letter by Edmund Shufflebottom.
Hypothesis: Shufflebottom has never forgiven me for beating him to a significant discovery some years ago. He wants me gone.
Facts (perhaps slightly colored by my current emotions): My disgrace is now complete. I must solve this mystery to save my job, my reputation, and most importantly, to prove to that meddling and self-righteous Shufflebottom that I am not making this up.