HELP!!

Hi guys, I need help finding a BL manga/manhwa in which the MC and ML are strangers but they are tied by red thread which means they are destined to be couple. IIRC it was set in high school...only the uke can see the red thread they are tied with. I don't remember the title nor the name of mangaka. I read it years ago and it was incompleted back then.. any hint would be much appreciated (づ￣ ³￣)づ