More Than Friends?

Ellyne and Henry are unseperatable. They were very very close. They really know each other. Each others likes, dislikes, favorites, hobbies and etc. They were best of friends. They treat each other as a big brother and little sister. No more no less.

But

Someone came back and it ruins everything.

Will Henry and Ellyne stay bestfriends or F.O(friendship over) or they will become more than friends?

Who could be that someone who ruin everything?

Ex? Crush? Friend?

In some other story PAST vs PRESENT
but this one is different.

PAST vs PAST

They are both in the past but one of them will be the present and maybe future