I think it was a oneshot in a collection of oneshots, but in the story, Kagome is a scientist and is the one in charge of Sesshoumaru, who was the product of two inuyoukai (both were experiments). He's very smart, can read and a famous writer, but even he doesn't know it. The people Kagome's under, encourage him to showcase his intelligence but won't let him leave his cell even though he wants to see the world outside. He's in love with Kagome and wants to be with her but Kagome can't be with him even though she's in love with him too, but apparently Sesshoumaru's father and another scientist fell in love and had a hanyou was born from it. Sesshoumaru's dad, though, went crazy because they kept his human mate and newborn away from him and had to take him out because he was dangerous so it's taboo for a scientist and experiment to be together. In the end, Kagome helps him escape and goes with him to an island with his mother and half brother and his half brother's mate in the end.

Sorry, it may not be much info, but any help in finding it would be great!