Lost a/b/o fic

I was giving rec to a friend on a/b/o fics but I JUST COULDN'T find one. It's an fic where Arthur is an omega and Uther force him to hide it. He makes him go to a remoted castle/house when he gets a heat. Merlin follow him there.

It's merthur There is no non-con or underage It was on ao3 Iirc it was complet Iirc there was no side ship

I loved this one so much 😭 please help