Specific Search: Merlin/Arthur non-con
I can't remember why, but I know that Merlin doesn't use magic and instead tries to fight back the normal way. I can't remember what happens afterwards, but I'm 90% sure that it leaves an opening for a manipulated!Arthur and a slightly insane!Merlin who doesn't hate Arthur, but instead Uther. I think it might have been posted over at the kinkme_merlin and the title had the word crops in it, I think.
Edit: Found by sonic_ish