Harry meets the new DADA prof, a member of the Order at Grimmauld, and after some flirting they mess around in the Black library. Around Christmastime she has to leave suddenly for some reason (an Order mission?) and hurriedly gives Harry a little pendant he can wear to talk to her via magic. But he doesn't really use it (something is blocking its magic?). The professor comes back eventually though.

Anyone remember something like this? This would be at least a few years old...

 

Yeah, that's enough of that.

 

Cool Story Bro.

 

Are they soul mates, and do they have to have their soul bonded to save her life in some part of the story....?

 

Actually, that sounds a bit like one of Thor Nairda's stories. Shadow Play, I believe it is. Quite dated, but it's in the library here.