When I was in my teens, so 1980s, I read a book from the library. For some reason I've been recently reminded of it but I can't remember much about it, the full title or who wrote it.
I'm sure it was called something "Connections". The only bit I can remember clearly is that the heroine went to a party and started talking to a boy/man with whom she felt an immediate and powerful connection. There may have been a third person involved. One of the onlookers made some comment about them and the person they were talking to said something like "yes, it's not often you see members of the Tuatha de Danann together in the same room these days" and I think there was some sort of transformation scene relating to Irish mythology.
Anyone remember it? It's driving me mad! I've googled "Connections Tuatha de Danann" and "Connections teen fiction" etc but unsurprisingly "connections" is too everyday a word to narrow it down.