Cheerilee, distinguished teacher of Ponyville, has been assigned to Caretaker of a unicorn to teach about "How to Live Sober" to the "student".
Once she reaches the unicorn's home however, she did not expect for the unicorn to be a stallion. Or to be quite..... unique. Mentally.
His name is Sherlock Holmes. He just moved to Ponyville all the way from Trottingham.
And his deduction skills are quite phenomenal.
As she will unfortunately soon find out.

(Crossover between Elementary and MLP. I own nothing.)